U.S. patent application number 13/218953 was filed with the patent office on 2012-05-31 for systems and methods employing low molecular weight gelators for crude oil, petroleum product or chemical spill containment and remediation.
This patent application is currently assigned to GEORGETOWN UNIVERSITY. Invention is credited to Ajaya Mallia Viswanatha Mallya, Richard G. Weiss.
Application Number | 20120136074 13/218953 |
Document ID | / |
Family ID | 46127044 |
Filed Date | 2012-05-31 |
United States Patent
Application |
20120136074 |
Kind Code |
A1 |
Weiss; Richard G. ; et
al. |
May 31, 2012 |
SYSTEMS AND METHODS EMPLOYING LOW MOLECULAR WEIGHT GELATORS FOR
CRUDE OIL, PETROLEUM PRODUCT OR CHEMICAL SPILL CONTAINMENT AND
REMEDIATION
Abstract
Low molecular weight gelators, methods of making such gelators,
organogels comprising such gelators and systems and methods of
using such gelators for the containment and/or remediation of a
release and/or spill of a crude oil, a petroleum product and/or a
chemical is described. In exemplary systems and methods, gels
and/or emulsions formed from the combination and/or contact of such
gelators and at least one of a crude oil, a petroleum product and a
chemical from a release and/or spill into the environment can be
used to recover these oils or chemicals while allowing the gelators
to be recovered and reused to clean up or contain additional crude
oil, petroleum products or chemicals.
Inventors: |
Weiss; Richard G.;
(Bethesda, MD) ; Viswanatha Mallya; Ajaya Mallia;
(Washington, DC) |
Assignee: |
GEORGETOWN UNIVERSITY
Washington
DC
|
Family ID: |
46127044 |
Appl. No.: |
13/218953 |
Filed: |
August 26, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13043200 |
Mar 8, 2011 |
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13218953 |
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61282609 |
Mar 8, 2010 |
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61346388 |
May 19, 2010 |
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61377408 |
Aug 26, 2010 |
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Current U.S.
Class: |
516/102 ;
210/198.1; 210/711; 405/128.75; 516/109 |
Current CPC
Class: |
A61K 2800/48 20130101;
C07C 235/06 20130101; C09K 3/32 20130101; A61Q 19/00 20130101; A61K
8/416 20130101; C07C 215/08 20130101; A61K 8/41 20130101; A23L
29/20 20160801; A61K 8/42 20130101 |
Class at
Publication: |
516/102 ;
516/109; 405/128.75; 210/711; 210/198.1 |
International
Class: |
B09C 1/08 20060101
B09C001/08; C02F 1/58 20060101 C02F001/58; C02F 1/68 20060101
C02F001/68; B01J 13/00 20060101 B01J013/00 |
Claims
1. A gel and/or emulsion composition comprising at least one of a
crude oil, a petroleum product and a chemical and a compound of
formula (I), (IV) or (V): ##STR00043## wherein: R.sub.1 is an alkyl
group of the formula C.sub.nH.sub.2n+1 or an aryl group, n is an
integer from 0 to 6, X is an anion, A is a hydrogen or a carbonyl,
and at least one of B, C, D, E, F, G and H is a hydroxyl group and
the others are hydrogen, and the compound of formula (I), (IV) or
(V) is in the (R) form.
2. The gel and/or emulsion composition of claim 1, wherein E is a
hydroxyl group.
3. The gel and/or emulsion composition of claim 2, wherein R.sub.1
is n-propyl or n-octadecyl.
4. The gel and/or emulsion composition of claim 3, wherein X.sup.-
is a halogen ion.
5. The gel and/or emulsion composition of claim 3, wherein X.sup.-
is chlorine ion.
6. A method of forming a gel and/or emulsion comprising at least
one of a crude oil, a petroleum product and a chemical, the method
comprising contacting and/or combining the at least one of the
crude oil, the petroleum product and the chemical with a compound
of formula (I), (IV) or (V): ##STR00044## wherein: R.sub.1 is an
alkyl group of the formula C.sub.nH.sub.2n+1 or an aryl group, n is
an integer from 0 to 6, X is an anion, A is a hydrogen or a
carbonyl, and at least one of B, C, D, E, F, G and H is a hydroxyl
group and the others are hydrogen, and the compound of formula (I),
(IV) or (V) is in the (R) form.
7. The method of claim 6, wherein E is a hydroxyl group.
8. The method of claim 7, wherein R.sub.1 is n-propyl or
n-octadecyl.
9. The method of claim 8, wherein X.sup.- is a halogen ion.
10. The method of claim 8, wherein X.sup.- is chlorine ion.
11. A method of containing the release and/or spill of at least one
of a crude oil, a petroleum product and a chemical, the method
comprising contacting and/or combining the at least one of the
crude oil, the petroleum product and the chemical with a compound
of formula (I), (IV) or (V): ##STR00045## wherein: R.sub.1 is an
alkyl group of the formula C.sub.nH.sub.2n+1 or an aryl group, n is
an integer from 0 to 6, X is an anion, A is a hydrogen or a
carbonyl, and at least one of B, C, D, E, F, G and H is a hydroxyl
group and the others are hydrogen, and the compound of formula (I),
(IV) or (V) is in the (R) form, to form a gel and/or emulsion
comprising the at least one of the crude oil, the petroleum product
and the chemical and the compound of formula (I), (IV) or (V).
12. The method of claim 11, further comprising collecting the gel
and/or emulsion.
13. The method of claim 12, further comprising converting the gel
and/or emulsion to form at least a first phase comprising
predominantly the at least one of the crude oil, the petroleum
product and the chemical and a second phase comprising the compound
of formula (I), (IV) or (V).
14. The method of claim 13, wherein E is a hydroxyl group.
15. The method of claim 14, wherein R.sub.1 is n-propyl or
n-octadecyl.
16. The method of claim 15, wherein X.sup.- is a halogen ion.
17. The method of claim 15, wherein X.sup.- is chlorine ion.
18. A method of recovering at least one of a crude oil, a petroleum
product and a chemical from a spill and/or release of the at least
one of the crude oil, the petroleum product and the chemical into
the environment, said method comprising: (a) contacting and/or
combining the at least one of the crude oil, the petroleum product
and the chemical with a compound of formula (I), (IV) or (V):
##STR00046## wherein: R.sub.1 is an alkyl group of the formula
C.sub.nH.sub.2n+1 or an aryl group, n is an integer from 0 to 6, X
is an anion, A is a hydrogen or a carbonyl, and at least one of B,
C, D, E, F, G and H is a hydroxyl group and the others are
hydrogen, and the compound of formula (I), (IV) or (V) is in the
(R) form, to form a gel and/or emulsion comprising the at least one
of the crude oil, the petroleum product and the chemical and the
compound of formula (I), (IV) or (V); (b) collecting the gel and/or
emulsion; and (c) converting the gel and/or emulsion to form at a
least first phase comprising predominantly the at least one of the
crude oil, the petroleum product and the chemical and a second
phase comprising the compound of formula (I), (IV) or (V).
19. The method of claim 18, wherein the gel and/or emulsion further
comprises water.
20. The method of claim 18, wherein in step (c) the second phase
further comprises water.
21. The method of claim 18, wherein step (b) comprises physical
removal of the gel and/or emulsion from the environment or removal
of the gel and/or emulsion from a contained system.
22. The method of claim 21, wherein the physical removal comprises
at least one of skimming and vacuuming the gel and/or emulsion from
at least one of a surface and a subsurface of water.
23. The method of claim 22, wherein the water is a body of water or
a volume of water collected from a volume of treated water
comprising the spill and/or release of the at least one of the
crude oil, the petroleum product and the chemical.
24. The method of claim 18, wherein E is a hydroxyl group.
25. The method of claim 24, wherein R.sub.1 is n-propyl or
n-octadecyl.
26. The method of claim 24, wherein X.sup.- is a halogen ion.
27. The method of claim 25, wherein X.sup.- is chlorine ion.
28. A system for containing and/or remediating a spill and/or
release of at least one of a crude oil, a petroleum product and a
chemical into the environment, the system comprising: (a) a
compound of formula (I), (IV) or (V): ##STR00047## wherein: R.sub.1
is an alkyl group of the formula C.sub.nH.sub.2n+1 or an aryl
group, n is an integer from 0 to 6, X is an anion, A is a hydrogen
or a carbonyl, and at least one of B, C, D, E, F, G and H is a
hydroxyl group and the others are hydrogen, and the compound of
formula (I), (IV) or (V) is in the (R) form, and (b) a means for
contacting and/or combining the compound of formula (I), (IV) or
(V) with the at least one of the crude oil, the petroleum product
and the chemical.
29. The system of claim 28, further comprising (c) a means for
collecting a gel and/or emulsion or composition formed upon contact
and/or combination of the compound of formula (I), (IV) or (V) with
the at least one of the crude oil, the petroleum product and the
chemical.
30. The system of claim 28, further comprising (d) a means for
separating the gel and/or emulsion comprising the compound of
formula (I), (IV) or (V) and the at least one of the crude oil, the
petroleum product and the chemical into a first phase comprising
predominantly the at least one of the crude oil, the petroleum
product and the chemical and a second phase comprising the compound
of formula (I), (IV) or (V).
31. The system of claim 30, wherein the second phase further
comprises water.
32. The system of claim 30, further comprises a means for
collecting at least one of the first phase and the second
phase.
33. The method of claim 28, wherein E is a hydroxyl group.
34. The method of claim 28, wherein R.sub.1 is n-propyl or
n-octadecyl.
35. The method of claim 28, wherein X.sup.- is a halogen ion.
36. The method of claim 28, wherein X.sup.- is chlorine ion.
37. The system of claim 28, wherein the means for contacting and/or
combining the compound of formula (I), (IV) or (V) with the at
least one of the crude oil, the petroleum product and the chemical
applies the compound of formula (I), (IV) or (V) onto or into the
at least one of the crude oil, the petroleum product and the
chemical to be contained or remediated and/or onto or into water
which is, or may become, in contact with the at least one of the
crude oil, the petroleum product and the chemical to be contained
or remediated.
38. The system of claim 32, wherein the means for collecting the
gel and/or emulsion formed upon contact of the compound of formula
(I), (IV) or (V) with the at least one of the crude oil, the
petroleum product and the chemical.
39. The system of claim 30, wherein the means for separating the
gel and/or emulsion comprising the compound of formula (I), (IV) or
(V) and the at least one of the crude oil, the petroleum product
and the chemical into a first phase comprising predominantly the at
least one of the crude oil, the petroleum product and the chemical
and a second phase comprising the compound of formula (I), (IV) or
(V) comprises placing a mixture comprising the first phase and the
second phase in a vessel and removing at least one of the phases
from the vessel.
Description
[0001] This application is a continuation-in-part (CIP) of U.S.
application Ser. No. 13/043,200, filed Mar. 8, 2011, which claims
priority to U.S. Provisional Application No. 61/282,609, filed Mar.
8, 2010 and U.S. Provisional Application No. 61/346,388, filed May
19, 2010, and this CIP application also claims priority to U.S.
Provisional Application No. 61/377,408, filed Aug. 26, 2010. Each
of these prior applications is hereby expressly incorporated by
reference in its entirety and is owned by the assignee hereof.
TECHNICAL FIELD
[0002] Low molecular weight gelators, methods of making such
gelators, organogels comprising such gelators, and systems and
methods of using such gelators to form gels that comprise at least
one of a crude oil, a petroleum product and a chemical for the
containment and/or remediation of an accidental and/or intentional
release of the at least one of the crude oil, the petroleum product
and/or the chemical are described. Systems and methods, wherein
gels, made from the combination of such gelators and at least one
of the crude oil, the petroleum product and/or the chemical from an
accidental and/or intentional release, can be used to recover these
oils or chemicals while allowing the gelators to be recovered and
reused to clean up or contain additional crude oil, petroleum
products or chemicals are also described. Exemplary systems and
methods for containing and/or remediating a spill and/or release of
at least one of a crude oil, a petroleum product and a chemical
from a spill and/or release into the environment using gelators are
also described. In other exemplary methods, the gelators can be
used in a variety of applications including the delivery of
pharmaceutical active pharmaceutical ingredients, in food,
cosmetics and consumer products.
BACKGROUND
[0003] Low molecular weight gelators, methods of making such
gelators, organogels comprising such gelators and methods of using
such organogels are described. Low molecular weight gelators which
are capable of gelling hydrogels and organogels, methods of making
such gelators, organogels comprising such gelators and methods of
using such organogels are described. Methods of using such gelators
to form gels which comprise at least one of a crude oil, a
petroleum product and a chemical which has been released into the
environment along with systems for containing and/or remediating a
spill and/or release of at least one of a crude oil, a petroleum
product and a chemical from a spill or release into the environment
using gelators have not been previously described. For at least the
reasons provided below, conventional low molecular weight gelators
and gels formed using the gelators are not optimal.
SUMMARY
[0004] This application relates to low molecular weight gelators
which can be used to produce organogels, methods of making such
gelators, organogels comprising such gelators and methods of using
such organogels. Such materials and methods are described. This
application also relates to low molecular weight gelators which are
capable of gelling hydrogels and organogels, methods of making such
gelators, organogels comprising such gelators and methods of using
such organogels. Such materials and methods are described. This
application also relates to gels and/or emulsions which comprise at
least one of a crude oil, a petroleum product and a chemical which
has been released into the environment and systems and methods that
use gels and/or emulsions made from the contacting and/or
combination of the gelators and oils or chemicals from spills,
and/or other accidental or intentional releases, to recover these
oils or chemicals while allowing the gelator to be recovered and
reused to clean up or contain additional crude oil, petroleum
products or chemicals. Systems for containing and/or remediating a
spill and/or release of at least one of a crude oil, a petroleum
product and a chemical from a spill or release into the environment
using such gelators are also described.
[0005] In an embodiment, a gelling agent is a compound of formula
(I):
##STR00001##
wherein, R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxyl group and the others are hydrogen, and
salts thereof, and the compound is in the (R) form, is a gelator
that can be used to form organogels.
[0006] In an embodiment, a gelling agent is a compound of formula
(II):
##STR00002##
wherein R is hydrogen or an alkyl group having from 1 to 18 carbon
atoms, and salts thereof, wherein the compound is in the (R) form,
is a gelator that can be used to form organogels.
[0007] In an embodiment, a gelling agent is compound of formula
(III):
##STR00003##
wherein R is hydrogen or an alkyl group having from 1 to 18 carbon
atoms, and salts thereof, wherein the compound is in the (R) form,
is a gelator that can be used to form organogels.
[0008] In an embodiment, a thixotropic gel comprises an organic
solvent and a compound of formula (I):
##STR00004##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxyl group and the others are hydrogen, and
salts thereof, and the compound is in the (R) form.
[0009] In an embodiment, a thixotropic gel comprises an organic
solvent and a compound of formula (II) or formula (III):
##STR00005##
wherein R is hydrogen or an alkyl group having from 1 to 18 carbon
atoms, and salts thereof, and the compound of formula (II) or
formula (III) is in the (R) form.
[0010] In an embodiment, a method of manufacturing
12-hydroxy-N-alkyloctadecanamides comprises: (a) adding a solution
of 12-hydroxystearamide and triethylamine in a non-reactive solvent
to a cooled solution of ethyl chloroformate in a non-reactive
solvent, and (b) adding an alkyl amine to the solution of step
(a).
[0011] In an embodiment, a method of manufacturing 1-(alkylamino)
octadecan-12-ols comprises the step of adding LAH to a suspension
of suspension of a 12-hydroxy-N-alkyloctadecanamide in dry THF
under a nitrogen atmosphere.
[0012] In an embodiment, a pharmaceutical composition comprises an
active pharmaceutical ingredient and a compound of formula (I):
##STR00006##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxyl group and the others are hydrogen, and
salts thereof, wherein the compound is in the (R) form, and a
pharmaceutically acceptable carrier.
[0013] In an embodiment, a food composition comprises a mixture of
a food and a compound of formula (I):
##STR00007##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxyl group and the others are hydrogen, and
salts thereof, wherein the compound is in the (R) form.
[0014] In an embodiment, a cosmetic composition comprises at least
one cosmetically acceptable ingredient and a compound of formula
(I):
##STR00008##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxyl group and the others are hydrogen, and
salts thereof, wherein the compound is in the (R) form, and a
pharmaceutically acceptable carrier.
[0015] In an embodiment, a consumer product comprises a compound of
formula (I):
##STR00009##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxyl group and the others are hydrogen, and
salts thereof, wherein the compound is in the (R) form, and an
acceptable medium.
[0016] In an embodiment, a method for containing an unintentional
chemical release, comprises forming a gel a compound of formula
(I):
##STR00010##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxyl group and the others are hydrogen, and
salts thereof, wherein the compound is in the (R) form with the
chemical that was unintentionally released.
[0017] In an embodiment, a gelling agent is a compound of formula
(IV):
##STR00011##
wherein R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group, n is an integer from 0 to 6, X is an anion, and
at least one of B, C, D, E, F, G and H is a hydroxyl group and the
others are hydrogen, and the compound is in the (R) form. In an
embodiment, E is a hydroxyl group. The gelling agent of formula
(IV) is a gelator that can be used to form an organogel or a
hydrogel.
[0018] In an embodiment, a thixotropic gel comprises an organic
solvent and a compound of formula (IV):
##STR00012##
wherein R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group, n is an integer from 0 to 6, X is an anion, and
at least one of B, C, D, E, F, G and H is a hydroxy and the others
are hydrogen, and the compound is in the (R) form. In another
embodiment, E is a hydroxyl group.
[0019] In an embodiment, a pharmaceutical composition comprises an
active pharmaceutical ingredient and a compound of formula
(IV):
##STR00013##
wherein R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group, n is an integer from 0 to 6, X is an anion, and
at least one of B, C, D, E, F, G and H is a hydroxy and the others
are hydrogen, and the compound is in the (R) form, and a
pharmaceutically acceptable carrier. In another embodiment, E is a
hydroxyl group.
[0020] In an embodiment, a processed food composition comprises a
food and a compound of formula (IV):
##STR00014##
wherein R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group, n is an integer from 0 to 6, X is an anion, and
at least one of B, C, D, E, F, G and H is a hydroxy and the others
are hydrogen, and the compound is in the (R) form, wherein the
compound is in the (R) form. In another embodiment, E is a hydroxyl
group. The group R.sup.1 in the compounds of formula (IV) can be
covalently attached to the nitrogen atom or can be present as the
counterion of the positively charged portion of the salt.
[0021] In an embodiment, a cosmetic composition comprises at least
one cosmetically acceptable ingredient and a compound of formula
(IV):
##STR00015##
wherein R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group, n is an integer from 0 to 6, X is an anion, and
at least one of B, C, D, E, F, G and H is a hydroxy and the others
are hydrogen, and the compound is in the (R) form, wherein the
compound is in the (R) form, and a cosmetically acceptable carrier.
In another embodiment, E is a hydroxyl group.
[0022] In an embodiment, a consumer product comprises a compound of
formula (IV):
##STR00016##
wherein R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group, n is an integer from 0 to 6, X is an anion, and
at least one of B, C, D, E, F, G and H is a hydroxy and the others
are hydrogen, and the compound is in the (R) form, wherein the
compound is in the (R) form, and an acceptable medium. In another
embodiment, E is a hydroxyl group.
[0023] In an embodiment, a method for containing an unintentional
chemical release, comprises forming a gel a compound of formula
(IV):
##STR00017##
wherein R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group, n is an integer from 0 to 6, X is an anion, and
at least one of B, C, D, E, F, G and H is a hydroxy and the others
are hydrogen, and the compound is in the (R) form, wherein the
compound is in the (R) form, with the chemical that was
unintentionally released. In another embodiment, E is a hydroxyl
group.
[0024] In an embodiment, a gel and/or emulsion composition
comprises at least one of a crude oil, a petroleum product and a
chemical and a compound of formula (I), (IV) or (V):
##STR00018##
wherein:
[0025] R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group,
[0026] n is an integer from 0 to 6,
[0027] X is an anion,
[0028] A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxyl group and the others are hydrogen,
[0029] and the compound is in the (R) form.
[0030] In an embodiment, a method of forming a gel and/or emulsion
comprising at least one of a crude oil, a petroleum product and a
chemical comprises contacting and/or combining the at least one of
the crude oil, the petroleum product and the chemical with a
compound of formula (I), (IV) or (V):
##STR00019##
wherein:
[0031] R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group,
[0032] n is an integer from 0 to 6,
[0033] X is an anion,
[0034] A is a hydrogen or a carbonyl, and
[0035] at least one of B, C, D, E, F, G and H is a hydroxyl group
and the others are hydrogen,
[0036] and the compound is in the (R) form.
[0037] In an embodiment, a method of containing a release and/or
spill of at least one of a crude oil, a petroleum product and a
chemical, comprises forming a gel and/or emulsion comprising the at
least one of the crude oil, the petroleum product and the chemical
and a compound of formula (I), (IV) or (V):
##STR00020##
wherein:
[0038] R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+,
or an aryl group,
[0039] n is an integer from 0 to 6,
[0040] X is an anion,
[0041] A is a hydrogen or a carbonyl, and
[0042] at least one of B, C, D, E, F, G and H is a hydroxyl group
and the others are hydrogen,
[0043] and the compound is in the (R) form.
[0044] In an embodiment, a method of recovering at least one of a
crude oil, a petroleum product and a chemical from a spill and/or
release into the environment comprises: (a) forming a gel and/or
emulsion comprising the at least one of the crude oil, the
petroleum product and the chemical and a compound of formula (I),
(IV) or (V); (b) collecting the gel and/or emulsion; and (c)
converting the gel and/or emulsion to form at least a first phase
comprising predominantly the at least one of the crude oil, the
petroleum product and the chemical and a second phase comprising
the compound of formula (I), (IV) or (V).
[0045] In an embodiment, a system for containing and/or remediating
a spill and/or release of at least one of a crude oil, a petroleum
product and a chemical from a spill and/or release into the
environment comprises: (a) a compound of formula (I), (IV) or (V);
and (b) a means for contacting and/or combining the compound of
formula (I), (IV) or (V) with the at least one of the crude oil,
the petroleum product and the chemical.
[0046] The applicability of the present teachings to other areas
will become apparent from the detailed description provided
hereinafter. It should be understood that the detailed description
and specific examples, while indicating certain embodiments of the
present teachings, are intended for purposes of illustration only
and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] FIG. 1 shows a representation of the design of LMOGs with
increasing complexity.
[0048] FIG. 2 shows the chemical structures of exemplary gelators
and analogous compounds without the hydroxyl group of exemplary
gelators.
[0049] FIG. 3 shows the chemical structures of exemplary gelators
of formulas 1-12.
[0050] FIG. 4 is a plot of the melting points (T.sub.mp) of the
neat amide gelators (1-6) (0) or the Tg values of their gels with
various liquids versus n, the number of carbon atoms in their
N-alkyl chains.
[0051] FIG. 5 is a plot of the melting points (T.sub.mp) of the
neat amine gelators (7-12) or the Tg values of their gels with
various liquids versus n, the number of carbon atoms in their
N-alkyl chains.
[0052] FIG. 6 is a plot of Tg values of silicone oil gels as a
function of concentration of exemplary gelling agents.
[0053] FIG. 7 is a plot of Tg values of toluene gels as a function
of concentration of exemplary agents.
[0054] FIG. 8 shows polarizing optical micrographs at 24.degree. C.
of 2 wt % 1 in (a, b) silicone oil and (c, d) toluene gels prepared
by (a, c) fast-cooling and (b, d) slow-cooling protocols.
[0055] FIG. 9 shows polarizing optical micrographs at 24.degree. C.
of gels of 2 wt % 4 in decane prepared by (a) fast-cooling and (b)
slow-cooling protocols.
[0056] FIG. 10 shows polarizing optical micrographs at 24.degree.
C. of gels of 2 wt % 4 in CCl.sub.4 prepared by (a) fast-cooling
and (b) slow-cooling protocols.
[0057] FIG. 11 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 4 in DMSO prepared by (a) fast-cooling and (b)
slow-cooling protocols.
[0058] FIG. 12 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 4 in toluene prepared by (a) fast-cooling and (b)
slow-cooling protocols.
[0059] FIG. 13 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 4 in silicone oil prepared by (a) fast-cooling
and (b) slow-cooling protocols.
[0060] FIG. 14 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 6 in decane prepared by (a) fast-cooling and (b)
slow-cooling protocols.
[0061] FIG. 15 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 6 in CCl.sub.4 prepared by (a) fast-cooling and
(b) slow-cooling protocols.
[0062] FIG. 16 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 6 in DMSO prepared by (a) fast-cooling and (b)
slow-cooling protocols.
[0063] FIG. 17 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 6 in silicone oil prepared by (a) fast-cooling
and (b) slow-cooling protocols.
[0064] FIG. 18 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 10 in CCl.sub.4 prepared by (a) fast-cooling and
(b) slow-cooling protocols.
[0065] FIG. 19 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 10 in decane prepared by (a) fast-cooling and (b)
slow-cooling protocols.
[0066] FIG. 20 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 10 in DMSO prepared by (a) fast-cooling and (b)
slow-cooling protocols.
[0067] FIG. 21 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 10 in toluene prepared by (a) fast-cooling and
(b) slow-cooling protocols.
[0068] FIG. 22 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 10 in silicone oil prepared by (a) fast-cooling
and (b) slow-cooling.
[0069] FIG. 23 shows polarizing optical micrographs (24.degree. C.)
of gels of 2 wt % 12 in silicone oil prepared by (a) fast-cooling
and (b) slow-cooling protocols.
[0070] FIG. 24 shows polarizing optical micrographs at 24.degree.
C. of gels of 0.42 wt % 6 in silicone oil prepared by (a)
fast-cooling and (b) slow-cooling protocols.
[0071] FIG. 25 is SEM images of xerogels prepared from (a) 2.0 wt 1
in CCl.sub.4, (b) 0.5 wt % 1 in CCl.sub.4, (c) 2.0 wt % 1 in
chlorobenzene, and (d) 0.5 wt % 1 in chlorobenzene.
[0072] FIG. 26 shows XRD patterns at 24.degree. C. of: (a) 4.8 wt %
1 in silicone oil gel after solvent subtraction; (b) neat 1; (c)
5.2 wt % 4 in silicone oil gel after solvent subtraction; (d) neat
4; (e) 5.0 wt % 6 in silicone oil gel after solvent subtraction;
and (f) neat 6.
[0073] FIG. 27 shows proposed packing arrangements of gelator
molecules in gel aggregates.
[0074] FIG. 28 shows X-ray diffractograms of
1-(propylamino)octadecan-12-01 (10) at 24.degree. C.: (a) 4.8 wt %
gel in silicone oil (after subtracting from neat silicone oil
diffractogram), (b) neat powder.
[0075] FIG. 29 shows IR spectra of (a) neat silicone oil, (b) a 5
wt % 1 in silicone oil gel.
[0076] FIG. 30 shows X-ray diffraction patterns of
1-octadecylaminooctadecan-12-ol (12) at 24.degree. C.: (a) 5.0 wt %
gel in silicone oil, and (b) neat powder.
[0077] FIG. 31 shows X-ray diffraction patterns of
1-aminooctadecan-12-ol (7) at 24.degree. C.: (a) 5.0 wt % gel in
silicone oil, and (b) neat powder.
[0078] FIG. 32 shows X-ray diffraction patterns of ammonium
carbamate salt of 1-aminooctadecan-12-ol (13) at 24.degree. C.: (a)
4.9 wt % gel in silicone oil, and (b) neat powder.
[0079] FIG. 33 shows Log-log strain sweep for a 2.0 wt % 1 in
silicone oil gel at 25 and 80.degree. C.
[0080] FIG. 34 shows Log-log frequency sweeps (0.1% strain) for a
2.0 wt % 1 in silicone oil gel at 25, 40, 60 and 80.degree. C.
[0081] FIG. 35 shows Log-log strain sweep (1.0 rad/sec) for a 2.0
wt % 4 in silicone oil gel at 25 and 75.degree. C.
[0082] FIG. 36 shows Time sweep (0.1% strain and 0.05 rad/s) at
45.degree. C. for a 2.0 wt % 12-hydroxy-N-propyloctadecanamide (4)
in silicone oil gel.
[0083] FIG. 37 shows log-log frequency sweep (0.1% strain) for a
2.0 wt % 12-hydroxy-N-propyloctadecanamide (4) in silicone oil gel
at 2, 35, 45, 55, and 65.degree. C.
[0084] FIG. 38 shows log-log strain sweep (1.0 rad/s) at 25 (blue)
and 50.degree. C. (red) for a 2.0 wt % 1-propylaminooctadecan-12-ol
(10) in silicone oil gel.
[0085] FIG. 39 shows log-log frequency sweep (0.05% strain) for a
2.0 wt % 1-propylaminooctadecan-12-ol (10) in silicone oil gel at
25, 35, 45 and 50.degree. C.
[0086] FIG. 40 shows G' and G'' as a function of time and
application of different strains and frequencies to a 2.0 wt % 1 in
silicone oil gel at 25.degree. C.
[0087] FIG. 41 shows G' and G'' as a function of time and
application of different strains and frequencies to a 2.0 wt % HSA
in silicone oil gel at 25.degree. C.
[0088] FIG. 42 shows G' and G'' as a function of time and
application of different strains and frequencies to a 2.0 wt % 2 in
silicone oil gel at 25.degree. C.
[0089] FIG. 43 shows G' and G'' as a function of time and
application of different strains and frequencies to a 2.1 wt % 4 in
silicone oil gel at 25.degree. C.
[0090] FIG. 44 shows G' and G'' as a function of time and
application of different strains and frequencies to a 2.1 wt % 10
in silicone oil gel at 25.degree. C.
[0091] FIG. 45 shows G' and G'' as a function of time and
application of different strains and frequencies to a 2.1 wt % 12
in silicone oil gel at 25.degree. C.
[0092] FIG. 46 shows a TGA plot of the weight loss of
1-aminooctadecan-12-ol (7) versus temperature.
[0093] FIG. 47 shows a TGA plot of the weight loss of 13, the
ammonium carbamate of 1-aminooctadecan-12-ol, versus
temperature.
[0094] FIG. 48 shows the chemical structures of exemplary gelators
of formulas 18-24.
[0095] FIG. 49 shows plots of the melting points (T.sub.mp) of the
neat 2-8 or the Tgel values of their 2 wt % gels with various
liquids versus the number of carbon atoms in their N-alkyl chains:
in water, in CCl.sub.4, and in toluene.
[0096] FIG. 50 shows (I) Tg values as a function of concentration
of 4 in A) toluene gels and B) hydrogels. (II) Tg values as a
function of concentration of 8 in toluene gels.
[0097] FIG. 51 shows polarizing optical micrographs (POM) at
23.degree. C. of 4 in toluene (A, B, 4.9 wt %), 4 in water (C, D,
4.8 wt %) and 8 in octanol (E, F, 1.9 wt %) gels.
[0098] FIG. 52 shows offset XRD diffractograms at 22.degree. C. of
A) (a) a gel consisting of 5.0 wt % 4 in toluene after empirical
subtraction of solvent diffractions, (b) neat 4 and (c) a gel
consisting of 5.1 wt % 4 in water after empirical subtraction of
solvent diffractions. (B) (a) a gel consisting of 4.9 wt % 8 in
toluene after empirical subtraction of solvent diffractions, (b)
neat 8 and (c) a gel consisting of 4.9 wt % 8 in octanol after
empirical subtraction of solvent diffractions.
[0099] FIG. 53 shows proposed packing arrangement of gelator
molecules of (A) 4 in hydrogel aggregates, (B) 4 in toluene gel
aggregates and (C) 8 in octanol gel aggregates from molecular
mechanics 2 (MM2) calculations.
[0100] FIG. 54 shows log-log strain sweep (1.0 rad/sec, (A)) and
log-log frequency sweep (0.1% strain, (B)) for a 2.1 wt % hydrogel
and a 2.1 wt .degree. A) toluene gel of 4 at 25.degree. C.
[0101] FIG. 55 shows water-motor oil mixtures with the addition of
various gelators.
DETAILED DESCRIPTION
[0102] Low molecular weight gelators which form organogels, methods
of making such gelators, organogels comprising such gelators and
methods of using such organogels are described. This application
also relates to low molecular weight gelators which are capable of
gelling hydrogels and organogels, methods of making such gelators,
organogels comprising such gelators and methods of using such
organogels. Such materials and methods are described. The low
molecular weight gelators can be used to produce gels and/or
emulsions comprising at least one of a crude oil, a petroleum
product and a chemical. Such gelators can be used in methods and
systems for containing and/or remediating the release of at least
one of a crude oil, a petroleum product and a chemical. The release
of the at least one of a crude oil, a petroleum product and a
chemical can be due to either accidental releases, such as spills,
shipping accidents or broken pipelines, or intentional
releases.
[0103] It is to be understood that this application is not limited
to particular embodiments described. It is also to be understood
that the terminology used herein is for the purpose of describing
particular embodiments only, and is not intended to be limiting,
since the scope of the present application will be limited only by
the appended claims.
[0104] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art. Although any methods and materials
similar or equivalent to those described herein can also be used in
the practice or testing of exemplary embodiments, specific
preferred methods and materials are now described.
[0105] As used herein, the recitation of a numerical range for a
variable is intended to convey that the variable can be equal to
any of the values within that range. Thus, for a variable which is
inherently discrete, the variable can be equal to any integer value
of the numerical range, including the end-points of the range.
Similarly, for a variable which is inherently continuous, the
variable can be equal to any real value of the numerical range,
including the end-points of the range. As an example, a variable
which is described as having values between 0 and 2, can be 0, 1 or
2 for variables which are inherently discrete, and can be 0.0, 0.1,
0.01, 0.001, or any other real value for variables which are
inherently continuous.
Definitions:
[0106] The following definitions are provided for specific terms
which are used in the following written description.
[0107] As used herein, the singular form "a", "an" and "the"
include plural references unless the context clearly dictates
otherwise. For example, the term "a cell" includes a plurality of
cells, including mixtures thereof.
[0108] As used herein, the term "about" means approximately, in the
region of, roughly, or around. When the term "about" is used in
conjunction with a numerical range, it modifies that range by
extending the boundaries above and below the numerical values set
forth. In general, the term "about" or "approximately" is used
herein to modify a numerical value above and below the stated value
by a variance of 20%.
[0109] As used herein, the term "aryl" refers to a monovalent
aromatic hydrocarbon group derived by the removal of one hydrogen
atom from a single carbon atom of a parent aromatic ring system, as
defined herein. Typical aryl groups include, but are not limited
to, groups derived from aceanthrylene, acenaphthylene,
acephenanthrylene, anthracene, azulene, benzene, chrysene,
coronene, fluoranthene, fluorene, hexacene, hexaphene, hexylene, a
s-indacene, s-indacene, indane, indene, naphthalene, octacene,
octaphene, octalene; ovalene, penta-2,4-diene, pentacene,
pentalene, pentaphene, perylene, phenalene, phenanthrene, picene,
pleiadene, pyrene, pyranthuene, rubicene, triphenylene,
trinaphthalene and the like. Preferably, an aryl group comprises
from 6 to 20 carbon atoms (C.sub.6-C.sub.20 aryl), more preferably
from 6 to 15 carbon atoms (C.sub.6-C.sub.15 aryl) and even more
preferably from 6 to 10 carbon atoms (C.sub.6-C.sub.10 aryl). More
preferably the aryl group is a naphthyl group or an anthranyl
group. Even more preferably, the aryl group is a napthyl group
bound at the 1- or 2-position or an anthranyl group bound at the
1-, 2- or 9-position.
[0110] The aryl group may be substituted with one or more of the
following substituents, which may be identical or different: a
halogen atom, a hydroxy group, a nitro group, a cyano group, an
amino group, a formyl group, a carbamoyl group, an aminosulfonyl
group, a lower alkyl group, a lower alkylamino group, a
hydroxy-lower alkylamino group, a di-lower alkylamino group, an
imino group, a lower alkylsulfonyl group, a lower
alkylsulfonylamino group, a lower alkoxy group, which may be
substituted with 1 to 3 halogen atom(s), a lower alkoxycarbonyl
group, a lower alkoxycarbonylamino group, a lower alkanoyl group
which may be substituted with 1 to 3 halogen atom(s), a carboxyl
group, a hydroxyiminomethyl group, a methoxyiminomethyl group, and
a lower alkylthio group.
[0111] The term "lower alkyl group" refers to a straight-chained or
branched alkyl group having 1 to 6 carbon atom(s), and examples
thereof include a methyl group, an ethyl group, a propyl group, an
isopropyl group, a butyl group, an isobutyl group, a sec-butyl
group, a tert-butyl group, a pentyl group, a hexyl group, and the
like.
[0112] The term "halogen atom" refers to a fluorine atom, a
chlorine atom, a bromine atom, an iodine atom.
[0113] The term "lower alkylamino group" refers to a substituent
formed by N-substitution of the above "lower alkyl group" to an
amino group, and examples thereof include an N-methylamino group,
an N-ethylamino group, an N-propylamino group, an N-isopropylamino
group, an N-butylamino group, an N-isobutylamino group, an
N-tert-butylamino group, an N-pentylamino group, an N-hexylamino
group, and the like.
[0114] The term "hydroxy-lower alkylamino group" refers to a
substituent formed by substitution of one or more of hydroxy
group(s) to the above "lower alkyl amino group", and examples
thereof include an N-hydroxyethylamino group, an
N-hydroxypropylamino group, an N-hydroxyisopropylamino group, an
N-hydroxybutylamino group, an N-hydroxyisobutylamino group, an
N-hydroxy-tert-butylamino group, an N-hydroxypentylamino group, an
N-hydroxyhexylamino group, and the like.
[0115] The term "di-lower alkylamino group" refers to a substituent
formed by N,N-disubstitution of the above "lower alkyl group" to an
amino group, and examples thereof include an N,N-dimethylamino
group, an N,N-diethylamino group, an N,N-dipropylamino group, an
N,N-diisopropylamino group, an N,N-dibutylamino group, an
N,N-diisobutylamino group, an N,N-ditert-butylamino group, an
N,N-dipentylamino group, an N,N-dihexylamino group, an
N-ethyl-N-methylamino group, an N-methyl-N-propylamino group, and
the like.
[0116] The term "lower alkylsulfonyl group" refers to a substituent
formed by the bonding of the above "lower alkyl group" to a sulfur
atom in a sulfonyl group, and examples thereof include a
methylsulfonyl group, an ethylsulfonyl group, a butylsulfonyl
group, and the like.
[0117] The term "lower alkylsulfonylamino group" refers to a
substituent formed by N-substitution of the above "lower
alkylsulfonyl group" to an amino group, and examples thereof
include a methylsulfonylamino group, an ethylsulfonylamino group, a
butylsulfonylamino group, and the like.
[0118] The term "lower alkoxy group" refers to a group formed by
the bonding of the "lower alkyl group" to an oxygen atom, and
examples thereof include a methoxy group, an ethoxy group, a
propoxy group, an isopropoxy group, a butoxy group, an isobutoxy
group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group,
a neopentyloxy group, a hexyloxy group, an isohexyloxy group, and
the like.
[0119] The term "lower alkoxycarbonyl group" refers to a group
formed by the bonding of the "lower alkoxy group" to a carbonyl
group, and specific examples thereof include a methoxycarbonyl
group, an ethoxycarbonyl group, a propoxycarbonyl group, an
isopropoxycarbonyl group, a butoxycarbonyl group, an
isobutoxycarbonyl group, a sec-butoxycarbonyl group, a
tert-butoxycarbonyl group, a pentyloxycarbonyl group, a
neopentyloxycarbonyl group, a hexyloxycarbonyl group, an
isohexyloxycarbonyl group, and the like.
[0120] The term "lower alkoxycarbonylamino group" refers to a group
formed by N-substitution of the "lower alkoxycarbonyl group" to an
amino group, and specific examples thereof include a
methoxycarbonylamino group, an ethoxycarbonylamino group, a
propoxycarbonylamino group, an isopropoxycarbonylamino group, a
butoxycarbonylamino group, an isobutoxycarbonylamino group, a
sec-butoxycarbonylamino group, a ten-butoxycarbonylamino group, a
pentyloxycarbonylamino group, a neopentyloxycarbonylamino group, a
hexyloxycarbonylamino group, an isohexyloxycarbonylamino group, and
the like.
[0121] The term "lower alkanoyl group" refers to a group formed by
the bonding of the "lower alkyl group" to a carbonyl group, and is
preferably a group in which the alkyl group having 1 to 5 carbon
atom(s) is bonded to a carbonyl group. For example, an acetyl
group, a propionyl group, a butyryl group, an isobutyryl group, a
valeryl group, an isovaleryl group, a pivaloyl group, a pentanoyl
group, and the like can be included.
[0122] The term "lower alkanoyloxy group" refers to a group formed
by bonding of the "lower alkanoyl group" to an oxygen atom, and
examples thereof include an acetyloxy group, a propionyloxy group,
a butyryloxy group, an isobutyryloxy group, a valeryloxy group, an
isovaleryloxy group, a pivaloyloxy group, a pentanoyloxy group, and
the like.
[0123] The term "lower alkylthio group" refers to a substituent
formed by the bonding of the "lower alkyl" to a sulfur atom, and
examples thereof include a methylthio group, an ethylthio group, a
butylthio group, and the like.
[0124] As used herein, the term LMOG means a low molecular-mass
organic gelator.
[0125] As used herein, the term HAS refers to
(R)-12-hydroxyoctadecanoic acid.
[0126] As used herein, the term SA refers to stearic acid, also
known as octadecanoic acid.
[0127] As used herein, the term SAFIN refers to self-assembled
fibrillar networks.
[0128] As used herein, the term critical gelator concentration
(CGC) refers to the lowest concentration of LMOG at which a gel is
formed at room temperature.
[0129] As used herein, the term thixotropy refers to the property
of certain gels that are thick (viscous) under normal conditions,
but flow (become thin, less viscous) over time when shaken,
agitated, or otherwise stressed.
[0130] As used herein, the term storage and loss modulus represents
the stored energy, representing the elastic portion, and the energy
dissipated as heat, representing the viscous portion measured in
gels.
[0131] As used herein, the term ambidextrous means that the gelator
can form hydrogels as well as organogels.
[0132] As used herein, the term "crude oil" means an unrefined
complex mixture of hydrocarbons of various molecular weights, and
other organic compounds, as can be found, for example, in geologic
formations beneath the earth's surface.
[0133] As used herein, the term "petroleum product" means
flammable, toxic, or corrosive products such as those that can be
obtained from distilling and processing of crude oil, unfinished
oils, natural gas liquids, blend stocks and other miscellaneous
hydrocarbon compounds.
[0134] As used herein, the term "chemical" means a substance that
is capable of forming a gel and/or emulsion when contacted and/or
combined with an exemplary gelator described herein.
[0135] The terms "crude oil", "petroleum product" and "chemical"
refer to substances that are capable of forming a gel and/or
emulsion when contacted and/or combined with the gelator described
herein. Such substances include, for example, hydrophilic
substances and substances which partition into the gel and/or
emulsion. Such substances generally have n-octanol/water partition
coefficients of greater than about 1,000.
[0136] As used herein, the term "released into the environment"
means that the crude oil, petroleum product or chemical has moved
from an intended area to an unintended and/or undesirable area.
This term includes accidental and/or intentional movement of the
material. Accidental movement includes, but is not limited to,
spills, leaks from containers including bottles, drums, pipes, and
containment vessels; leaks or discharge of material from
transportation vehicles, such as cars, trucks, ships and planes;
and leaks from material transport systems, such as pipelines and
conveyors. Intentional movement includes, but is not limited to,
the releases described above, where the cause of the movement was
intentionally performed. Such causes include, but are not limited
to, criminal or terrorist activity and combat-related discharges,
such as the release of oil from oil wells, ships, refineries and
terminals during the Gulf war.
[0137] As a result of their potential applications and fundamental
importance, gels made with low molecular-mass organic gelators
(LMOGs) have experienced increasing interest in recent years..sup.1
The LMOGs self-assemble primarily by 1D growth modes.sup.2 to form
fibers, strands, or tapes via relatively weak physical molecular
interactions such as van der Waals forces, intermolecular H
bonding, electrostatic forces, .pi.-.pi. stacking, or even London
dispersion forces. How these weak physical interactions affect the
formation, strength, and stability of a gel must be understood in
order to design organogels with the desired properties.
[0138] The range of structures known to be LMOGs is extremely
broad. It includes molecules as simple as n-alkanes.sup.3-5 (a in
FIG. 1) and as complex as substituted steroids or salts made by the
addition of two components..sup.1,6 Thus, London dispersion forces
must play a dominant stabilizing role in networks made by the LMOG,
n-hexatriacontane (C36),.sup.4 because it lacks the functional
groups that are necessary for the other favorable intermolecular
interactions. Carboxylic acids with long alkyl chains (e.g., b in
FIG. 1), such as stearic acid (SA; i.e., octadecanoic acid), offer
the possibility of additional intermolecular interactions (N.B., H
bonding) within the LMOG assemblies. In that regard, when cooled
below a characteristic temperature (Tg), solutions of relatively
high concentrations of long-chained saturated fatty acids and their
salts are known to form gelatinous materials with fibrous
substructures..sup.7
[0139] Structure c in FIG. 1 represents LMOGs with two different
functional groups attached to an n-alkane. Interesting examples of
such LMOGs with secondary amide groups are
11-(butylamido)undecanoic acid,.sup.8 the odium salt of N-octadecyl
maleamic acid (a hydrogelator),.sup.9 and
N-3-hydroxypropyldodecanamide.sup.10 as well as a naturally
occurring carboxylic acid (available from castor oil.sup.11),
12-hydroxystearic acid (HSA; i.e., 12-hydroxyoctadecanoic acid
(FIG. 1)),.sup.12 which is easily obtained as its (R) enantiomer.
Enantiopure HSA exhibits circular dichroic signals that are
attributed to helical arrangements of the molecules in their
fibrillar networks..sup.12d,12e Previous reports showed that alkali
metal salts of HSA have twisted fibrous networks in their gel
state..sup.12f-12i
[0140] The link between the molecular structure of a gelator and
either its efficiency in constructing the self-assembled fibrillar
networks (SAFINs) of gels or the nature of those SAFINs is not
obvious..sup.13 Many LMOGs are polymorphous, and it is known that
small changes in molecular structure can lead to large changes in
crystal packing. For example, primary amides generally form
tapelike structures whereas secondary amides form chainlike
structures;.sup.14 urea is able to form clathrates in the presence
of long n-alkanes, but N,N'-dialkylureas as small as
N,N'-dimethylurea organize into fibers and SAFINs, leading to
gels..sup.15 Thus, it is important to investigate the relationship
between molecular structure and gelation properties in a series of
molecules that differ structurally in a rational way.
[0141] Such an investigation is presented here for molecules of the
c- and d-types in Scheme 1 using HSA as the base structure. Also,
comparisons are made with gels containing LMOGs derived from SA
(i.e., b- and e-type molecules that are analogs of HSA in which the
12-hydroxyl group has been removed). The affect of modifying the
terminal functional group of HSA on the gelating properties was
evaluated by systematically modifying the structure by introducing
nitrogen-containing moieties. This data, and the complementary
information from the SA analogs, were used to identify the factors
that appear to be most important in generating very efficient LMOGs
of molecules with long alkyl chains as their primary structural
unit. Exemplary derivatives of HSA are amides 1-6 and amines 7-12
and the ammonium carbamate salt of 7, compound 13. The underlying
concepts behind the choice of these molecules are that H bonding
between amides can be stronger than between amines and that the
N-alkyl groups and charged centers at the head groups of 13 can
modify the molecular packing of the LMOGs within their fibrillar
aggregates. The availability of gelation data from the parent
molecule, HSA, and from several nitrogen-containing derivatives of
the corresponding acid without a hydroxyl moiety, SA (b- and e-type
gelators in FIG. 1), allowed structure-gelation correlations to be
derived.
[0142] The data demonstrate that the introduction of a 12-hydroxyl
group and the presence of a primary amide group increase the
efficiency of the gelators. This assessment is based upon gelation
temperatures, temporal stabilities (the time between when gels were
prepared in sealed containers at .about.24.degree. C. and when they
undergo visual phase separation or flowed when inverted), critical
gelator concentrations (CGCs; the lowest concentrations of LMOG at
which a gel is formed at room temperature), and ranges of liquids
gelated. The stabilities of the gels are then correlated with the
structures of the LMOGs and their SAFINs. Furthermore, some of the
gels exhibit exceedingly fast and high degrees of recovery of their
viscoelastic properties after their shear-induced destruction; they
are thixotropic. Although fast recovery of viscoelasticity has been
found in hydrogels where the SAFIN is composed of amorphous
objects,.sup.16 we are not aware of other examples in which the
fibrillar objects are crystalline and the liquids are organic, as
they are here.
[0143] Embodiments of various compounds useful as gelling agents,
thixotropic gels formed using such gelling agents, products in
which such gelling agents can be employed, and methods of using
such gelling agents are described below.
[0144] In an embodiment, a gelling agent is a compound of formula
(I):
##STR00021##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxy and the others are hydrogen, and salts
thereof, wherein the compound is in the (R) form. In another
embodiment, R is hydrogen or an alkyl group having from 1 to 18
carbon atoms. In another embodiment, in the compound of formula
(I), R is hydrogen or an alkyl group having 1, 2, 3, 4 or 18 carbon
atoms. In still another embodiment, only one of B, C, D, E, F, G
and H is a hydroxy group and the others are hydrogen.
[0145] In another embodiment, a gelling agent is a compound of
formula (II):
##STR00022##
wherein R is hydrogen or an alkyl group having from 1 to 18 carbon
atoms, and salts thereof, wherein the compound is in the (R) form.
In yet another embodiment, in the compound of formula (II), R is
hydrogen or an alkyl group having 1, 2, 3, 4 or 18 carbon atoms. In
still another embodiment, only one of B, C, D, E, F, G and H is a
hydroxy group and the others are hydrogen.
[0146] In another embodiment, a gelling agent is a compound of
formula (III):
##STR00023##
wherein R is hydrogen or an alkyl group having from 1 to 18 carbon
atoms, and salts thereof, wherein the compound is in the (R) form.
In still another embodiment, in the compound of formula (III), R is
hydrogen or an alkyl group having 1, 2, 3, 4 or 18 carbon atoms. In
still another embodiment, only one of B, C, D, E, F, G and H is a
hydroxy group and the others are hydrogen.
[0147] In an embodiment, a thixotropic gel comprises an organic
solvent and a compound of formula (I):
##STR00024##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxy and the others are hydrogen, and salts
thereof, wherein the compound is in the (R) form. In another
embodiment, R is hydrogen or an alkyl group having from 1 to 18
carbon atoms. In another embodiment, in the compound of formula
(I), R is hydrogen or an alkyl group having 1, 2, 3, 4 or 18 carbon
atoms. In still another embodiment, only one of B, C, D, E, F, G
and H is a hydroxy group and the others are hydrogen. In an
embodiment, the gel is formed from at least one solvent is selected
from the group consisting of n-hexane, n-octane, n-decane, silicone
oil, methanol, 1-butanol, 1-octanol, benzyl alcohol, chlorobenzene,
chloroform, carbon tetrachloride, benzene, toluene,
dimethylsulfoxide, acetonitrile and combinations thereof.
[0148] In an embodiment, in the above gel, the compound of formula
(I) is present at a concentration of about 20% or less, on a
weight/weight basis. In another embodiment, the compound of formula
(I) is present at a concentration of about 10%, on a weight/weight
basis, in the above gel. In yet another embodiment, the compound of
formula (I) is present at a concentration of about 5% or less, n a
weight/weight basis, in the above gel. In another embodiment, the
compound of formula (I) is present at a concentration of about 2%,
on a weight/weight basis, in the above gel. In yet another
embodiment, the compound of formula (I) is present at a
concentration of about 2% or less, on a weight/weight basis, in the
above gel. In another embodiment, the compound of formula (I) is
present at a concentration of about 0.5%, on a weight/weight basis,
in the above gel. In yet another embodiment, the compound of
formula (I) is present at a concentration of about 0.2% or less, n
a weight/weight basis, in the above gel.
[0149] In yet another embodiment, the above gel recovers at least
about 80% of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear. In still another embodiment, the gel recovers at least about
90% of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear. In a further embodiment, the gel recovers at least about 95%
of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear.
[0150] In a still further embodiment, the gel recovers at least
about 98% of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear.
[0151] In an embodiment, a thixotropic gel comprises at least one
solvent and a compound of formula (II) or formula (III):
##STR00025##
wherein R is hydrogen or an alkyl group having from 1 to 18 carbon
atoms, and salts thereof, wherein the compound is in the (R) form.
In an embodiment, the gel is formed from at least one solvent is
selected from the group consisting of n-hexane, n-octane, n-decane,
silicone oil, methanol, 1-butanol, 1-octanol, benzyl alcohol,
chlorobenzene, chloroform, carbon tetrachloride, benzene, toluene,
dimethylsulfoxide, acetonitrile and combinations thereof.
[0152] In an embodiment, in the above gel, the compound of formula
(II) or (III) is present at a concentration of about 20% or less,
on a weight/weight basis. In another embodiment, the compound of
formula (II) or (III) is present at a concentration of about 10%,
on a weight/weight basis, in the above gel. In yet another
embodiment, the compound of formula (II) or (III) is present at a
concentration of about 5% or less, n a weight/weight basis, in the
above gel. In another embodiment, the compound of formula (II) or
(III) is present at a concentration of about 2%, on a weight/weight
basis, in the above gel. In yet another embodiment, the compound of
formula (II) or (III) is present at a concentration of about 2% or
less, on a weight/weight basis, in the above gel. In another
embodiment, the compound of formula (II) or (III) is present at a
concentration of about 0.5%, on a weight/weight basis, in the above
gel. In yet another embodiment, the compound of formula (II) or
(III) is present at a concentration of about 0.2% or less, n a
weight/weight basis, in the above gel.
[0153] In yet another embodiment, the above gel recovers at least
about 80% of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear. In still another embodiment, the gel recovers at least about
90% of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear. In a further embodiment, the gel recovers at least about 95%
of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear.
[0154] In a still further embodiment, the gel recovers at least
about 98% of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear.
[0155] In an embodiment, 12-hydroxy-N-alkyloctadecanamides are
manufactured by (a) adding a solution of 12-hydroxystearamide and
triethylamine in a dry non-reactive solvent to a solution of ethyl
chloroformate in a dry non-reactive solvent while maintaining the
temperature at about 0.degree. C.; and (b) adding an alkyl amine to
the solution obtained in step (a).
[0156] In another embodiment, 1-(alkylamino)octadecan-12-ols are
manufactured by adding LAH to a suspension of suspension of a
12-hydroxy-N-alkyloctadecanamide in a dry non-reactive solvent
under an inert atmosphere.
[0157] In an embodiment, a pharmaceutical composition comprises an
active pharmaceutical ingredient and a compound of formula (I):
##STR00026##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxy group and the others are hydrogen, and
salts thereof, wherein the compound is in the (R) form, and a
pharmaceutically acceptable carrier. In another embodiment, R is
hydrogen or an alkyl group having from 1 to 18 carbon atoms. In
another embodiment, in the compound of formula (I), R is hydrogen
or an alkyl group having 1, 2, 3, 4 or 18 carbon atoms. In still
another embodiment, only one of B, C, D, E, F, G and H is a hydroxy
group and the others are hydrogen.
[0158] In another embodiment, a processed food composition
comprises a food and a compound of formula (I):
##STR00027##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxy and the others are hydrogen, and salts
thereof, wherein the compound is in the (R) form. In another
embodiment, R is hydrogen or an alkyl group having from 1 to 18
carbon atoms. In another embodiment, in the compound of formula
(I), R is hydrogen or an alkyl group having 1, 2, 3, 4 or 18 carbon
atoms. In still another embodiment, only one of B, C, D, E, F, G
and H is a hydroxy group and the others are hydrogen.
[0159] In another embodiment, a cosmetic composition comprising at
least one cosmetically acceptable ingredient and a compound of
formula (I):
##STR00028##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxy and the others are hydrogen, and salts
thereof, wherein the compound is in the (R) form, and a
cosmetically acceptable carrier. In another embodiment, R is
hydrogen or an alkyl group having from 1 to 18 carbon atoms. In
another embodiment, in the compound of formula (I), R is hydrogen
or an alkyl group having 1, 2, 3, 4 or 18 carbon atoms. In still
another embodiment, only one of B, C, D, E, F, G and H is a hydroxy
group and the others are hydrogen.
[0160] In an embodiment, a consumer product comprises a compound of
formula (I):
##STR00029##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxy and the others are hydrogen, and salts
thereof, wherein the compound is in the (R) form, and an acceptable
medium. In another embodiment, R is hydrogen or an alkyl group
having from 1 to 18 carbon atoms. In another embodiment, in the
compound of formula (I), R is hydrogen or an alkyl group having 1,
2, 3, 4 or 18 carbon atoms. In still another embodiment, only one
of B, C, D, E, F, G and H is a hydroxy group and the others are
hydrogen.
[0161] In an embodiment, a method for containing an unintentional
chemical release, comprises forming a gel a compound of formula
(I):
##STR00030##
wherein R is hydrogen or an alkyl group having from 1 to 36 carbon
atoms, A is a hydrogen or a carbonyl, and at least one of B, C, D,
E, F, G and H is a hydroxy and the others are hydrogen, and salts
thereof, wherein the compound is in the (R) form with the chemical
that was unintentionally released. In another embodiment, R is
hydrogen or an alkyl group having from 1 to 18 carbon atoms. In
another embodiment, in the compound of formula (I), R is hydrogen
or an alkyl group having 1, 2, 3, 4 or 18 carbon atoms. In still
another embodiment, only one of B, C, D, E, F, G and H is a hydroxy
group and the others are hydrogen.
[0162] In another embodiment, at least one compound of formula (II)
or (III) is used as the compound of formula (I) in any of the above
embodiments.
[0163] In an embodiment, a gelling agent is a compound of formula
(IV):
##STR00031##
wherein n is an integer from 0 to 6, X is an anion, A is a hydrogen
or a carbonyl, and at least one of B, C, D, E, F, G and H is a
hydroxy and the others are hydrogen, and the compound is in the (R)
form, wherein the compound forms an organogel or a hydrogel upon
mixing with an organic solvent or an aqueous solution. In another
embodiment, the anion is selected from the group consisting of
chlorine, bromine, iodine, nitrate, boron trifluoride, acetate,
nonanoate and oxalate.
[0164] In an embodiment, a thixotropic gel comprises an organic
solvent and a compound of formula (IV):
##STR00032##
wherein n is an integer from 0 to 6, X is an anion, A is a hydrogen
or a carbonyl, and at least one of B, C, D, E, F, G and H is a
hydroxy and the others are hydrogen, and the compound is in the (R)
form. In another embodiment, only one of B, C, D, E, F, G and H is
a hydroxy group and the others are hydrogen. In an embodiment, the
anion is selected from the group consisting of chlorine, bromine,
iodine, nitrate, boron trifluoride, acetate, nonanoate and oxalate.
In another embodiment, the at least one solvent is selected from
the group consisting of n-hexane, n-octane, n-decane, silicone oil,
methanol, 1-butanol, 1-octanol, benzyl alcohol, chlorobenzene,
chloroform, carbon tetrachloride, n-perfluorooctane, benzene,
toluene, dimethylsulfoxide, acetonitrile and water.
[0165] In an embodiment, in the above gel, the compound of formula
(IV) is present at a concentration of about 20% or less, on a
weight/weight basis. In another embodiment, the compound of formula
(IV) is present at a concentration of about 10%, on a weight/weight
basis, in the above gel. In yet another embodiment, the compound of
formula (IV) is present at a concentration of about 5% or less, n a
weight/weight basis, in the above gel. In another embodiment, the
compound of formula (IV) is present at a concentration of about 2%,
on a weight/weight basis, in the above gel. In yet another
embodiment, the compound of formula (IV) is present at a
concentration of about 2% or less, on a weight/weight basis, in the
above gel. In another embodiment, the compound of formula (IV) is
present at a concentration of about 0.5%, on a weight/weight basis,
in the above gel. In yet another embodiment, the compound of
formula (IV) is present at a concentration of about 0.2% or less, n
a weight/weight basis, in the above gel.
[0166] In yet another embodiment, the gel recovers at least about
80% of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear. In still another embodiment, the gel recovers at least about
90% of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear. In a further embodiment, the gel recovers at least about 95%
of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear.
[0167] In a still further embodiment, the gel recovers at least
about 98% of its viscoelasticity within less than about one minute,
preferably within less than about 30 seconds, and more preferably
within less than about 15 seconds after exposure to destructive
shear.
[0168] In an embodiment, a pharmaceutical composition comprises an
active pharmaceutical ingredient and a compound of formula
(IV):
##STR00033##
wherein n is an integer from 0 to 6, X is an anion, A is a hydrogen
or a carbonyl, and at least one of B, C, D, E, F, G and H is a
hydroxy and the others are hydrogen, and the compound is in the (R)
form, and a pharmaceutically acceptable carrier. In another
embodiment, only one of B, C, D, E, F, G and H is a hydroxy group
and the others are hydrogen.
[0169] In an embodiment, a processed food composition comprises a
food and a compound of formula (IV):
##STR00034##
wherein n is an integer from 0 to 6, X is an anion, A is a hydrogen
or a carbonyl, and at least one of B, C, D, E, F, G and H is a
hydroxy and the others are hydrogen, and the compound is in the (R)
form, wherein the compound is in the (R) form. In still another
embodiment, only one of B, C, D, E, F, G and H is a hydroxy group
and the others are hydrogen.
[0170] In an embodiment, a cosmetic composition comprises at least
one cosmetically acceptable ingredient and a compound of formula
(IV):
##STR00035##
wherein n is an integer from 0 to 6, X is an anion, A is a hydrogen
or a carbonyl, and at least one of B, C, D, E, F, G and H is a
hydroxy and the others are hydrogen, and the compound is in the (R)
form, wherein the compound is in the (R) form, and a cosmetically
acceptable carrier. In still another embodiment, only one of B, C,
D, E, F, G and H is a hydroxy group and the others are
hydrogen.
[0171] In an embodiment, a consumer product comprises a compound of
formula (IV):
##STR00036##
wherein n is an integer from 0 to 6, X is an anion, A is a hydrogen
or a carbonyl, and at least one of B, C, D, E, F, G and H is a
hydroxy and the others are hydrogen, and the compound is in the (R)
form, wherein the compound is in the (R) form, and an acceptable
medium. In still another embodiment, only one of B, C, D, E, F, G
and H is a hydroxy group and the others are hydrogen.
[0172] In an embodiment, a method for containing an unintentional
chemical release, comprises forming a gel a compound of formula
(IV):
##STR00037##
wherein n is an integer from 0 to 6, X is an anion, A is a hydrogen
or a carbonyl, and at least one of B, C, D, E, F, G and H is a
hydroxy and the others are hydrogen, and the compound is in the (R)
form, wherein the compound is in the (R) form, with the chemical
that was unintentionally released. In still another embodiment,
only one of B, C, D, E, F, G and H is a hydroxy group and the
others are hydrogen.
[0173] The group R.sup.1 in the compounds of formula (IV) can be
covalently attached to the nitrogen atom or can be present as the
counterion of the positively charged portion of the salt.
[0174] In an embodiment, a gel and/or emulsion comprises at least
one of a crude oil, a petroleum product and a chemical from an
accidental and/or intentional release and a compound of formula
(I), (IV) or (V):
##STR00038##
wherein:
[0175] R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group,
[0176] n is an integer from 0 to 6,
[0177] X is an anion,
[0178] A is a hydrogen or a carbonyl, and
[0179] at least one of B, C, D, E, F, G and H is a hydroxyl group
and the others are hydrogen,
[0180] and the compound is in the (R) form.
[0181] In an embodiment, E is a hydroxyl group. In another
embodiment, R.sub.1 is n-propyl or n-octadecyl. In a further
embodiment, X.sup.- is a halogen ion. In yet another embodiment,
X.sup.- is chlorine ion.
[0182] In an embodiment, a method of containing the release and/or
spill of at least one of a crude oil, a petroleum product and a
chemical comprises forming a gel and/or emulsion comprising the at
least one of the crude oil, the petroleum product and the chemical
and a compound of formula (I), (IV) or (V):
##STR00039##
wherein:
[0183] R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group,
[0184] n is an integer from 0 to 6,
[0185] X is an anion,
[0186] A is a hydrogen or a carbonyl, and
[0187] at least one of B, C, D, E, F, G and H is a hydroxyl group
and the others are hydrogen,
[0188] and the compound is in the (R) form.
[0189] In an embodiment, E is a hydroxyl group. In another
embodiment, R.sub.1 is n-propyl or n-octadecyl. In a further
embodiment, X.sup.- is a halogen ion. In yet another embodiment,
X.sup.- is chlorine ion. In another embodiment, the method further
comprises collecting the gel and/or emulsion. In still another
embodiment, the method further comprises converting the gel and/or
emulsion to form at least a first phase comprising predominantly
the at least one of the crude oil, the petroleum product and the
chemical and a second phase comprising the compound of formula (I),
(IV) or (V). In a further embodiment, the phase comprising the
compound of formula (I), (IV) or (V) is separated from the phase
comprising the at least one of the crude oil, the petroleum product
and the chemical and a second phase comprising the compound of
formula (I), (IV) or (V) by placing a mixture comprising the first
phase and the second phase in a vessel and removing at least one of
the phases from the vessel. In another embodiment, the separation
of the phases is enhanced by contacting the mixture with a
chemically inert device, such as, for example, a screen or filter
to release the first phase from the mixture. The compound of
formula (I), (IV) or (V) which has been separated from the first
phase can be recovered and re-used in additional containment and/or
remediation activities.
[0190] In an embodiment, a method of recovering at least one of a
crude oil, a petroleum product and a chemical from a spill and/or
release of the at least one of the crude oil, the petroleum product
and the chemical into the environment comprises: (a) forming a gel
and/or emulsion comprising the at least one of the crude oil, the
petroleum product and the chemical and a compound of formula (I),
(IV) or (V):
##STR00040##
wherein:
[0191] R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group,
[0192] n is an integer from 0 to 6,
[0193] X is an anion,
[0194] A is a hydrogen or a carbonyl, and
[0195] at least one of B, C, D, E, F, G and H is a hydroxyl group
and the others are hydrogen,
[0196] and the compound is in the (R) form; and
(b) collecting the gel and/or emulsion; and (c) converting the gel
and/or emulsion to form at least a first phase comprising
predominantly the at least one of the crude oil, the petroleum
product and the chemical and a second phase comprising the compound
of formula (I), (IV) or (V). In an embodiment, E is a hydroxyl
group. In another embodiment, R.sub.1 is n-propyl or n-octadecyl.
In a further embodiment, X.sup.- is a halogen ion. In yet another
embodiment, X.sup.- is chlorine ion. In another embodiment, the gel
and/or emulsion further comprises water. In yet another embodiment,
the second phase in step (c) further comprises water. In a further
embodiment, the step of collecting the gel and/or emulsion
comprises physical removal of the gel and/or emulsion from the
environment or removal of the gel and/or emulsion from a contained
system. Physical removal of the gel and/or emulsion can be
performed using a number of methods known to one of ordinary skill
in the art including skimming and/or vacuuming the gel and/or
emulsion from the surface and/or a subsurface region of a body or
volume of water. In an embodiment, the water is a body of water or
a volume of water collected from a volume of treated water
comprising the spill and/or release of the at least one of the
crude oil, the petroleum product and the chemical. The water may be
a body of water, such as an ocean, gulf, bay, harbor, lake, pond,
reservoir, river, bayou, stream, creek, canal, marsh, lagoon, or
other type of recognized accumulations of water. The water may also
be an accumulation of water used in emergency response, such as
firefighting, as well as other accumulations of water where the
water has come in contact with a crude oil, a petroleum product,
and/or a chemical for which it is desirable to remove such material
from the water.
[0197] In an embodiment, a system for containing and/or remediating
a spill and/or release of at least one of a crude oil, a petroleum
product and a chemical into the environment comprises: (a) compound
of formula (I), (IV) or (V):
##STR00041##
wherein
[0198] R.sub.1 is an alkyl group of the formula C.sub.nH.sub.2n+1
or an aryl group,
[0199] n is an integer from 0 to 6,
[0200] X is an anion,
[0201] A is a hydrogen or a carbonyl, and
[0202] at least one of B, C, D, E, F, G and H is a hydroxyl group
and the others are hydrogen,
[0203] and the compound is in the (R) form; and
(b) a means for contacting and/or combining the compound of formula
(I), (IV) or (V) with the at least one of the crude oil, the
petroleum product and the chemical. In another embodiment, the
system further comprises (c) a means for collecting a gel and/or
emulsion or composition formed upon contact and/or combination of
the compound of formula (I), (IV) or (V) with the at least one of
the crude oil, the petroleum product and the chemical. In yet
another embodiment, the system further comprises (d) a means for
separating the gel and/or emulsion or composition comprising the
compound of formula (I), (IV) or (V) and the at least one of the
crude oil, the petroleum product and the chemical into a first
phase comprising predominantly the at least one of the crude oil,
the petroleum product and the chemical and a second phase
comprising the compound of formula (I), (IV) or (V). In still
another embodiment, the second phase further comprises water. In a
further embodiment, the system further comprises a means for
collecting at least one of the first phase and the second phase. In
an embodiment, E is a hydroxyl group. In another embodiment,
R.sub.1 is n-propyl or n-octadecyl. In a further embodiment,
X.sup.- is a halogen ion. In yet another embodiment, X.sup.- is
chlorine ion. In an embodiment, the means for contacting and/or
combining the compound of formula (I), (IV) or (V) with the at
least one of the crude oil, the petroleum product and the chemical
comprises applying the compound of formula (I), (IV) or (V) onto or
into the spill and/or release of the at least one of the crude oil,
the petroleum product and the chemical to be contained or
remediated and/or onto or into water which is, or may become, in
contact with the at least one of the crude oil, the petroleum
product and the chemical to be contained or remediated. In another
embodiment, the compound of formula (I), (IV) or (V) can be
contained within one or more bags or other devices which can be
placed on, or into, the at least one of the crude oil, the
petroleum product and the chemical to be contained or remediated
and/or onto or into water which is, or may become, in contact with
the at least one of the crude oil, the petroleum product and the
chemical to be contained or remediated. In another embodiment, the
one or more bags can comprise a water-soluble material such that
the bags dissolve and/or form openings upon contact with the water
and/or the at least one of the crude oil, the petroleum product and
the chemical to be contained or remediated, thus allowing the
compound of formula (I), (IV) or (V) to come in contact with the at
least one of the crude oil, the petroleum product and the chemical
to be contained or remediated. In still another embodiment, the
compound of formula (I), (IV) or (V) can be contained within
containment devices, such as booms or tubes which can be placed on,
or into, the at least one of the crude oil, the petroleum product
and the chemical to be contained or remediated, or can be placed in
water around an area containing the at least one of the crude oil,
the petroleum product and chemical to be contained or
remediated.
[0204] In embodiments where the compound of formula (I), (IV) or
(V) is contacted and/or combined with the at least one of the crude
oil, the petroleum product and the chemical to be contained or
remediated, the embodiment can, of course, employ any one these
compounds alone, a combination of any two compounds, or all three,
and variations thereof. It is preferable that the compound be
dissolved or dispersed in a water-miscible solvent, when contacted
and/or combined with the at least one of the crude oil, the
petroleum product and the chemical. Exemplary solvents can be
easily removed by evaporation. Exemplary solvents include, but are
not limited, to lower alkyl alcohols, such as methanol, ethanol,
and propanol; ketones, such as acetone; acetonitrile;
tetrahydrofuran; and p-dioaxane, combinations thereof and the like.
An exemplary solvent will allow the composition comprising the
solvent and the compound of formula (I), (IV) or (V) to form a gel
and/or emulsion when contacted and/or combined with the at least
one of the crude oil, the petroleum product and the chemical.
Exemplary solvents can also exhibit limited or almost no toxicity
to organisms exposed to the solvent. It is within the capabilities
of one of ordinary skill in the art to select an appropriate
solvent.
[0205] The present disclosure will be further understood with
reference to the following non-limiting examples.
EXAMPLES
Instrumentation and Procedures:
[0206] .sup.1H-NMR spectra were recorded on a Varian 300 MHz
spectrometer interfaced to a Sparc UNIX computer using Mercury
software. Chemical shifts were referenced to an internal standard,
tetramethylsilane (TMS). IR spectra were obtained on a Perkin-Elmer
Spectrum One FTIR spectrometer interfaced to a personal computer.
Elemental analyses were performed on a Perkin-Elmer 2400 CHN
elemental analyzer using acetanilide as a calibration standard.
Melting points and optical micrographs (POMs) were recorded on a
Leitz 585 SM-LUX-POL microscope equipped with crossed polars, a
Leitz 350 heating stage, a Photometrics CCD camera interfaced to a
computer, and an Omega HH503 microprocessor thermometer connected
to a J-K-T thermocouple. The samples for POM were flame sealed in
0.4 or 0.5 mm path-length, flattened Pyrex capillary tubes
(VitroCom) heated to their liquid phase in a boiling water bath and
cooled according to protocols described below.
[0207] Powder X-ray diffraction (XRD) patterns of samples were
obtained on a Rigaku R-AXIS image plate system with Cu Ka X-rays
(A=1.54 A) generated by a Rigaku generator operating at 46 kV and
40 mA with the collimator at 0.5 mm (to obtain 0.5-mm-diameter
beams of X-rays17). Data processing and analyses were performed
using Materials Data JADE (version 5.0.35) XRD pattern processing
software. Samples were sealed in 0.5 mm glass capillaries (W.
Muller, Schonwalde, Germany), and diffraction data were collected
for 2 hours (neat powders) or 10 hours (gels).
[0208] Differential scanning calorimetry (DSC) and
thermogravimetric analyses (TGA) were performed on a TA 2910
differential scanning calorimeter interfaced to a TA Thermal
Analyst 3100 controller under a slow stream of nitrogen flowing
through the cell. Samples were in closed aluminum pans for DSC and
in open ones for TGA measurements. Transition temperatures from DSC
(T.sub.m) are reported at the onsets of endotherms (on heating) and
exotherms (on cooling). Heating rates were 5.degree. C./min;
cooling rates were variable and depended on the difference between
the cell block and ambient temperature.
[0209] Rheological measurements were obtained on an Anton Paar
Physica MCR 301 rheometer using Peltier controlled parallel plates
(25 mm diameter). The gap between the parallel plates was 0.5 mm
unless indicated otherwise, and the data were collected using
Rheoplus/32 Service V3.10 software. Before data were recorded, each
sample was placed between the shearing plates of the rheometer and
heated to 120.degree. C. to ensure that a solution/sol was present.
It was cooled to 10.degree. C. (at .about.20.degree. C.
min.sup.-1), the temperature was increased to 25.degree. C., and
the sample was incubated there for 15 min to reform the gel and
remove any shear-induced alignment of the fibers of SAFIN.
[0210] Scanning electron microscopy (SEM) images were recorded with
2-30 kV electron beam energies on a Zeiss Supra 55 VP electron
scanning microscope. Samples for SEM were prepared by placing the
gel sample on an Al mount (1/200 slotted head, 1/800 pin, Ted
Pella, Inc.) and allowing the solvent to evaporate at 24.degree. C.
for 24 h. No metal coating was applied.
Example 1
Preparation of Gelling Agents
[0211] Materials. Silicone oil (tetramethyltetraphenylsiloxane, Dow
silicone oil 704 from Dow Chemical Company, Midland, Mich.) was
used as received Solvents for syntheses and other liquids for
gelation studies were reagent grade or better (Aldrich). Anhydrous
THF (Acros Chemicals), LiAlH.sub.4 (LAH, 95%, Aldrich),
triethylamine (99.5%, Aldrich), NH.sub.4OH (ACS reagent, Fisher),
and stearic acid (Aldrich, 99%) were used as received. Thionyl
chloride (>99%, Aldrich) was distilled immediately before use.
Dry CO.sub.2 was prepared by passing gas formed from dry ice
through an anhydrous calcium sulfate (Drierite) tube. Methylamine
(2 M solution in THF, Aldrich), ethylamine (2 M solution in THF,
Aldrich) and butylamine (99.5%, Aldrich) were used as received.
1-Octadecylamine (Aldrich) was purified by collecting a center
fraction from two distillations under reduced pressure at
160-165.degree. C. (1 torr) and was stored under a nitrogen
atmosphere at 5-6.degree. C.
[0212] Purification of HSA. Commercial HSA (25 g; mp:
58.6-80.3.degree. C., Arizona Chemicals) was dissolved in 300 mL of
a warm 1:19 (v:v) mixture of ethyl acetate:hexane. The solution was
then allowed to cool very slowly while being stirred vigorously to
avoid gelation. This procedure was repeated twice more to yield 17
g of HSA, mp 80.2-82.1.degree. C. (lit.sup.1 80.5-81.0.degree.
C.).
[0213] .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta. 0.91 (t, 3H,
CH.sub.3, J=6.2 Hz), 1.3-1.45 (m, 26H, --CH.sub.2) 1.68 (m, 2H,
--CH.sub.2), 2.37 (t, 2H, CH.sub.2--CO.sub.2H, J=7.2 Hz), 3.6 (m,
1H, CH--OH); elemental analysis; calcd for C.sub.18H.sub.36O.sub.3:
C, 71.95; H, 12.08; found: C, 72.22; H, 12.14.
[.alpha.].sup.D-0.49.degree. (0.141 g/mL, pyridine)..sup.2
(lit.sup.1 [.alpha.].sup.D-0.41.degree. (0.168 g/mL, pyridine)
[0214] Stearamide (8). The amide was prepared by a common recipe.
Thionyl chloride (0.6 g, 6 mmol) was slowly added to stearic acid
(1.0 g, 3.5 mmol) and the mixture was heated at 55.degree. C. for 2
h under a dry atmosphere. Excess thionyl chloride was removed by
distillation and the remaining liquid (stearoyl chloride) was
slowly added to 15 mL of an aqueous 30% ammonia solution at
0.degree. C. The precipitate that formed was collected by vacuum
filtration and was recrystallized from ethyl acetate to yield 0.7 g
(70%) of product, mp 108.6-109.0.degree. C. (lit.sup.4
108.4.degree. C.).
[0215] 12-Hydroxystearamide (1). The preparation of 1 was performed
according to a literature procedure. Ethyl chloroformate (18.0 g,
166 mmol) was added slowly to cooled (<0.degree. C.); dry THF
(100 mL) stirred under a nitrogen atmosphere. The mixture was
stirred for 20 more min followed by slow addition of HSA (10.0 g,
33 mmol) and triethylamine (2.3 g, 33 mmol) in dry THF (50 mL)
while maintaining the temperature below 0.degree. C. The contents
were stirred for another 30 min and a stream of anhydrous ammonia
gas (prepared from an NH.sub.4OH solution (50 mL) in a hot (ca
60.degree. C.) water bath; the gas was passed through a 50.times.2
cm column filled with anhydrous Drierite and ca 20 g of activated
CaO powder (prepared by heating CaCO.sub.3 to ca 500.degree. C. for
30 min and cooling in a desiccator under a nitrogen atmosphere) was
bubbled rapidly through the solution for 10 min. The mixture was
kept for 12 h without stirring, during which time the temperature
slowly rose to room temperature. The solvent was removed by
distillation and the residue, after being dissolved in ethyl
acetate (200 mL), was washed successively with 3 N aq HCl
(3.times.15 mL), aqueous 1 M Na.sub.2CO.sub.3 (3.times.15 mL), and
brine (3.times.10 mL). During these washings, the amide in the
organic phase formed a gel which was destroyed by warming the outer
surface of the separatory funnel. The organic part was collected,
dried with anhydrous sodium sulfate, decanted while hot, and then
slowly cooled to 0.degree. C. with vigorous stirring. The
precipitate that formed was collected by filtration. This process
was repeated once and the solid was dried in vacuo at 55-60.degree.
C. for 12 h to yield 9.3 g (94%), mp 113.1-113.7.degree. C.
(lit.sup.6 111-112.degree. C.).
[0216] IR (neat): 3412, 3302, 3209 (NH and OH), 2913, 2848 (CH),
1650 (CO) cm.sup.-1; .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta.
0.92 (t, 3H, CH.sub.3, J=6.1 Hz), 1.3-1.6 (m, 30H, CH.sub.2), 2.2
(2H, t, CH.sub.2--CO, J=7.1 Hz), 3.61 (1H, m, CH--OH), 5.4 (2H, br,
CONH.sub.2); elemental analysis; calcd for
C.sub.18H.sub.37NO.sub.2; C, 72.19; H, 12.45; N, 4.68; O, 10.68;
found: C, 72.55; H, 12.57; N, 4.97.
[0217] 1-Aminooctadecan-12-ol (7) and its ammonium carbamate salt
(13). LAH (5.0 g, 130 mmol) was slowly added to a stirred
suspension of 1 (5.0 g, 17 mmol) in dry THF (250 mL) under a
nitrogen atmosphere. Then, the mixture was heated to reflux and the
gel that formed was broken with a spatula. Refluxing was continued
overnight, excess LAH was destroyed by successively adding (very
slowly; Caution: exothermic reaction.) 6 mL of water, 6 mL of aq
15% NaOH, and 12 mL of water. The mixture was filtered, and the
filtrate was concentrated and dissolved in 30 mL of ethyl acetate.
A precipitate that formed as the ethyl acetate solution was cooled
to 0.degree. C. was separated by filtration and recrystallized from
ethyl acetate to afford 4.5 g (94%) of amine7, mp 60.0-61.5.degree.
C. IR (neat): 3303, 3209 (NH and OH), 2955, 2913, 2848 (CH)
cm.sup.-1; .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta. 0.91 (t, 3H,
CH.sub.3, J=6.2 Hz), 1.3-1.5 (32H, m, CH.sub.2), 2.7 (2H, t,
CH.sub.2--NH.sub.2, J=6.9 Hz), 3.63 (1H, m, CH--OH). Elemental
analysis; calcd for 12-hydroxystearamine monohydrate: C, 71.28; H,
13.53; N, 4.62; found: C, 71.78; H, 13.40; N, 4.64. Thermal
gravimetric analysis (TGA) showed a weight loss between room
temperature and 103.degree. C. of 5.7% (FIG. 46); 5.9% calculated
for loss of one molecule of water.
[0218] The ammonium carbamate salt (13) was prepared by bubbling
CO.sub.2 gas through a chloroform solution of the amine 13 for 20
min. The salt precipitated quantitatively and was collected by
filtration: mp 77.7-80.0.degree. C. on first heating;
59.2-61.2.degree. C. on second heating (corresponding to
regeneration of 7). TGA of 13 showed a weight loss of 6.6% between
room temperature and 103.degree. C. (FIG. 47); 6.7% is the
calculated weight loss for one molecule of carbon dioxide.
Preparation of 12-Hydroxy-N-alkyloctadecanamides
[0219] 12-Hydroxy-N-alkyloctadecanamides were prepared by the
following procedure. To a cooled (at 0.degree. C.) and vigorously
stirred solution of ethyl chloroformate (18.0 g, 166 mmol) in dry
THF (50 mL) was added slowly a solution of HSA (10.0 g, 33 mmol)
and triethylamine (2.3 g, 33 mmol) in dry THF (50 mL) while
maintaining the temperature at 0.degree. C. The mixture was stirred
for an additional 20 min. An alkyl amine (33 mmol) in 50 mL dry THF
was added to the solution at 0.degree. C., and the reaction mixture
was kept at room temperature for 24 h. The solvent was removed
under vacuum and the residue was dissolved in ethyl acetate (50
mL), washed successively with 3N HCl (3.times.15 mL), aqueous 1M
Na.sub.2CO.sub.3 (3.times.15 mL), and water (50 mL). The organic
layer was dried over sodium sulfate and the residue, after
evaporation, was recrystallized from ethyl acetate.
[0220] 12-Hydroxy-N-methyloctadecanamide (2): 49% yield; mp
108.2-108.8.degree. C.; .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta.
0.91 (t, 3H, CH.sub.3, J=6.8 Hz), 1.2-1.6 (m, 28H, --CH.sub.2),
2.15 (t, 2H, --CH.sub.2--CO--, J=7.6 Hz), 2.81 (d, 3H, CH.sub.3,
J=4.8 Hz), 3.58 (m, 1H, --CH--OH), 5.4 (br, 1H, --NH--); elemental
analysis calcd for C.sub.19H.sub.39NO.sub.2: C, 72.79; H, 12.34; N,
4.38; O, 10.21; found: C, 72.63; H, 12.34; N, 4.38.
[0221] 12-Hydroxy-N-ethyloctadecanamide (3): 93% yield; mp
111.0-111.3.degree. C.; .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta.
0.91 (t, 3H, CH.sub.3, J=6.8 Hz), 1.13 (t, 3H, J=7.2 Hz) 1.2-1.6
(m, 26H, --CH.sub.2), 2.17 (t, 2H, --CH.sub.2--CO--, J=7.5 Hz),
3.21-3.28 (q, 2H, --CH--NH, J=7.2 Hz) 3.58 (m, 1H, --CH--OH), 5.3
(br, 1H, --NH--), elemental analysis calcd for
C.sub.20H.sub.41NO.sub.2: C, 73.34; H, 12.62; N, 4.28; O, 9.77;
found: C, 73.33; H, 12.48; N, 4.29.
[0222] 12-Hydroxy-N-propyloctadecanamide (4): 93% yield; mp
107.3-107.4.degree. C.; .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta.
0.91 (m 6H, CH.sub.3) 1.2-1.6 (m, 28H, --CH.sub.2), 2.17 (t, 2H,
--CH.sub.2--CO--, J=7.5 Hz), 3.21-3.28 (q, 2H, --CH--NH, J=7.2 Hz)
3.59 (m, 1H, --CH--OH), 5.3 (br, 1H, --NH--); elemental analysis
calcd for C.sub.21H.sub.43NO.sub.2: C, 73.84; H, 12.69; N, 4.10; O,
9.37; found: C, 74.16; H, 12.95; N, 4.33.
[0223] 12-Hydroxy-N-butyloctadecanamide (5): 94% yield; mp
104.1-104.6.degree. C.; .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta.
0.92 (m, 6H, CH.sub.3), 1.2-1.6 (m, 30H, --CH.sub.2), 2.17 (t, 2H,
--CH.sub.2--CO--, J=7.4 Hz), 3.21-3.27 (q, 2H, --CH--NH, J=7.2 Hz),
3.59 (m, 1H, --CH--OH), 5.3 (br, 1H, --NH--). elemental analysis
calcd for C.sub.19H.sub.39NO.sub.2: C, 74.31; H, 12.76; N, 3.94; O,
9.00; found: C, 73.85; H, 12.61; N, 3.92.
[0224] 12-Hydroxy-N-octadecyloctadecanamide (6): 47% yield; mp
106.9-107.3.degree. C.; .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta.
0.92 (m, 6H, CH.sub.3), 1.2-1.6 (m, 60H, --CH2), 2.17 (t, 2H,
--CH.sub.2--CO--, J=7.4 Hz), 3.21-3.27 (q, 2H, --CH--NH, J=7.2 Hz),
3.59 (m, 1H, --CH--OH), 5.3 (br, 1H, --NH--); elemental analysis
calcd for C.sub.36H.sub.73NO.sub.2: C, 78.33; H, 13.33; N, 2.54; O,
5.80; found: C, 78.88; H, 13.65; N, 2.76.
Preparation of 1-(Alkylamino)octadecan-12-ols
[0225] 1-(Alkylamino)octadecan-12-ols were prepared by the
following procedure. LAH (3.0 g, 79 mmol) was added slowly to a
stirred suspension of a 12-hydroxy-N-alkyloctadecanamide (15 mmol)
in dry THF (200 mL) under a nitrogen atmosphere. Then, the mixture
was refluxed overnight, excess LAH was destroyed by successively
adding very slowly a total of 3 mL of water in small amounts, 15%
aq NaOH solution (a total of 3 mL), and 3 mL of water. The mixture
was filtered and the filter pad was washed with THF. The combined
liquids were concentrated on a rotary evaporator and dissolved in
ethyl acetate (30 mL). The amine that precipitated upon cooling the
ethyl acetate solution to 0.degree. C. was recrystallized from
ethyl acetate and hexane mixture (1:4).
[0226] 1-(Methylamino)octadecan-12-ol (8). 91% yield; mp
88.0-88.5.degree. C.; 1H-NMR (CDCl.sub.3, 300 (MHz): .delta. 0.89
(t, 3H, CH.sub.3, J=6.0 Hz), 1.2-1.6 (m, 30H, --CH.sub.2), 2.4, (s,
3H, CH.sub.3), 2.55 (t, 2H, --CH.sub.2--NH--, J=6.8 Hz), 3.6 (m,
1H, --CH--OH). elemental analysis calcd for C.sub.19H.sub.41NO: C,
76.19; H, 13.80; N, 4.68; O, 5.34; found: C, 76.27; H, 13.80; N,
4.52.
[0227] 1-(Ethylamino)octadecan-12-ol (9). 92% yield; mp
84.3-84.8.degree. C.; 1H-NMR (CDCl.sub.3, 300 (MHz): .delta. 0.9
(t, 3H, CH.sub.3, J=6.0 Hz), 1.1 (t, 3H, CH.sub.3, J=6.8 Hz)
1.2-1.6 (m, 30H, --CH.sub.2), 2.6 (m, 4H, --CH.sub.2--NH--), 3.6
(m, 1H, --CH--OH). elemental analysis calcd for C.sub.20H.sub.43
NO: C, 76.61; H, 13.82; N, 4.47; O, 5.10; found: C, 76.78; H,
13.85; N, 4.46.
[0228] 1-(Propylamino)octadecan-12-ol (10). 92% yield; mp
87.6-88.0.degree. C.; .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta.
0.93 (m, 6H, CH.sub.3), 1.2-1.6 (m, 32H, --CH.sub.2), 2.6 (m, 4H,
--CH.sub.2--NH--), 3.6 (m, 1H, --CH--OH); elemental analysis calcd
for C.sub.21H.sub.45NO: C, 76.99; H, 13.85; N, 4.28; O, 4.88;
found: C, 77.51; H, 14.41; N, 4.52.
[0229] 1-(Butylamino)octadecan-12-ol (11). Yield 65%; mp
89.3-89.8.degree. C.; 1H-NMR (CDCl.sub.3, 300 (MHz): .delta. 0.92
(m, 6H, CH.sub.3), 1.2-1.6 (m, 34H, --CH.sub.2), 2.6 (m, 4H,
--CH.sub.2--NH--), 3.59 (m, 1H, --CH--OH). elemental analysis calcd
for C.sub.22H.sub.47NO: C, 77.35; H, 13.87; N, 4.10; O, 4.68;
found: C, 77.45; H, 13.95; N, 4.12.
[0230] 1-(Octadecylamino)octadecan-12-ol (12). Yield 96%; mp
92.8-93.4.degree. C.; .sup.1H-NMR (CDCl.sub.3, 300 (MHz): .delta.
0.92 (m, 6H, CH.sub.3), 1.2-1.6 (m, 64H, --CH.sub.2), 2.6 (m, 4H,
--CH.sub.2--NH--), 3.59 (m, 1H, --CH--OH); elemental analysis calcd
for C.sub.36H.sub.75NO: C, 80.37; H, 14.05; N, 2.60; O, 2.97;
found: C, 79.69; H, 14.51; N, 2.82.
Example 2
Fast and Slow Cooling Procedures for the Preparation of Gels from
Sols and Analyses of Gels
[0231] Fast-cooled gels were prepared by placing weighed amounts of
a liquid and gelator into a glass tube (5 mm i.d.) that was then
flame-sealed. The mixture was heated to ca. 80.degree. C. in a
water bath (or to 110.degree. C. in an oil bath with 1) until a
solution/sol was obtained and was then placed directly into an
ice-water bath for 10 min. After the sample was warmed to room
temperature for 1 h, its appearance was noted. Slow-cooled gels
were prepared using the protocol above except that the hot
solutions/sols were kept in the water or oil bath while they
returned slowly to room temperature.
Example 3
Temperatures of Gelation and Critical Gelation Concentrations
(CGC)
[0232] Gelation temperatures (Tg) were determined by the inverse
flow method.sup.18 (i.e., the temperature ranges over which a gel
fell under the influence of gravity when inverted in a sealed glass
tube that was placed in a water bath that was heated from room
temperature at ca. 1.5.degree. C. min.sup.-1). CGCs were determined
from a series of fast-cooled gels with different LMOG
concentrations; the concentration of the one with the lowest
gelator concentration that did not fall when inverted at 24.degree.
C. is reported.
[0233] The gelation properties of 2 wt HSA and compounds 1-13 in a
wide range of liquids are summarized in Tables 1 and 2.
TABLE-US-00001 TABLE 1 Apprearances,.sup.a T.sub.g Values (.degree.
C.), and Periods of Stability.sup.b (in Parentheses) of Gels
Containing 2 wt % HSA and Its Amide Derivatives ( 1-6) in Various
Liquids liquid HSA 1 2 3 4 5 6 n-hexane OG OG OG OG OG OG OG (59
60, 2 m) (syn, 91 92,.sup.c 4 m) (syn, 82 83, >3 w) (syn,
81,.sup.c >1 m) (syn, 82,.sup.c 2 m) (syn, 74 75,.sup.c >1 m)
(syn, 78,.sup.c 2 m) n-octane OG OG OG OG OG OG OG (60-62, >9
m.sup.d) (94-95,.sup.c 4 m) (84-85,.sup.c >3 w) (84,.sup.c >1
m) (syn, >90,.sup.c 3 m) (74,.sup.c >1 m) (syn, 81,.sup.c 2
m) a-drecane OG OG OG OG OG P OG (64-65, >9 m) (95-96,.sup.c
>1 y) ( >87,.sup.c >3 w) (89-90,.sup.c >1 m) (syn,
>90,.sup.c >1 y) (syn, 83,.sup.c >1 y) silicone oil OG OG
OG OG OG OG (73 74, >9 m) (98 100, >1 y) (90 91, >1 m) (86
87, >1 m) (83 85, >1 y) (82 84, >1 m) (83 84, >1 y)
methanol soln soln P soln soln soln P 1-butanol soln soln soln soln
soln P visc soln 1-octanol soln OG P P soln P visc soln (syn,
27-34, >1 y) benzyl alcohol soln soln soln soln soln soln visc
soln chlorobenzene CG CG OG OG OG OG OG (46-48, > 9 m) (63-64,
>1 y) (56-57, >3 w) (49-50, >1 m (52, >1 y) (46, >1
m (55-57, >1 y).sup.e chloroform OG OG P soln soln soln P
(21-22) (syn, 38, 4 m) CCl.sub.4 CG OG OG OG OG OG OG I visc soln
(syn, 41, >9 m) (syn, 63,.sup.c 4 m) (syn, 68-69, >3 w) (syn,
64-66, >1 m (syn, 58-60, 2 d) (syn, 59-60, >1 m
n-perfluorooctane I I I I I I I benzene CG CG OG OG OG OG P (49-50,
5 m) (64-65, 7 m.sup.d) (58-60, >3 w) (57-61, >1 m 54-55, 2
m) (47, >1 m) toluene CG CG OG OG OG OG OG (44-45, 9 m.sup.d)
(65-67, >1 y.sup.e) (61-62, >3 w) (57-58, >1 m (55-58,
>1 y.sup.d) (syn, 51, >1 m (syn, 58, 5 m) DMSO soln soln OG
OG OG OG OG (45-47, >3 w) (44-47, >1 m) (57, >1 y) (55-56,
>1 m) (syn, 74-75, 2 d) acetonitrile OG OG OG OG OG OG P (45 48,
2 m) (53 54, 2 m) (59 60,.sup.c >3 w) (56,.sup.c >1 m) (62, 2
m) (55,.sup.c >1 m) water I I I I I I I .sup.aOG--opaque gel,
syn--syneresis, soln--solution, visc--viscous, P--precipitate,
I--insoluble, CG--clear gel, y--year, m--month., d--day, w--week.
.sup.bThe periods of stability were measured as the time between
when gels were prepured in sealed containers at ~24.degree. C. and
when they underwent phase separation that could be detected
visually, temporal stabilities of gels with T.sub.g below
24.degree. C. were not measured. .sup.cPhase separation: liquid
fell upon heating, some or all solid did not. .sup.dSyneresis after
2 months. .sup.eSyneresis after 8 months.
TABLE-US-00002 TABLE 2 Appearances,.sup.a T.sub.g Values (.degree.
C.), and Periods of Stability.sup.b (in Parentheses) of Gels
Containing 2 wt % Amine Derivatives of HSA (7 12) and the Ammonium
Carbamate Salt of 7 (13) in Various Liquids liquid 7 8 9 10 11 12
13 n -hexane P P P OG P P P (syn, 40-41, 2 d) n-octane P P P OG
(syn, 46, 1 w) P P P n -decane P P P OG (49, 1 m) P P P silicone
oil OG (21-22) OG OG OG OG OG OG (0-2) (57-58, >3 w) (55-56,
>1 m) (62-63, >1 y) (62-64, >1 m) (67-69, >1 y)
methanol soln soln soln P soln P P 1-butanol soln soln soln soln
soln visc soln P 1-octanol soln P soln soln soln visc soln visc
soln benzyl alcohol soln soln soln soln soln soln + P P
chlorobenzeene soln soln visc soln visc soln soln P OG (54-55, 5 m)
chloroform CG soln soln soln soln visc soln OG (syn, 34-35, 4 m)
(syn, 39-40, >1 y) CCl.sub.4 visc soln TG OG OG TG visc soln
soln (syn, 69-70,.sup.c >1 m) (74-75,.sup.c >1 y) (72-74,
>1 m) n-perfluorooctane I I I I I I I benzene soln soln soln P
soln P P toluene visc soln soln soln OG soln P soln (syn. 33-35, 1
h) DMSO visc soln OG OG OG (59-60, 2 m) OG OG soln (36-42, >3 w)
(syn, 33-36, >1 m) (55-56, >2 m) (63-83, 2 m) acetonitrile P
P P P P P P water I I I I I I I .sup.aOG--opaque gel,
syn--syneresis, soln--solution, visc--viscous, P--precipitate,
I--insoluble, TG--translucent gel, CG--clear gel, y--year,
m--month, d--day, w--week. .sup.bThe periods of stability were
measured as the time between when gels were prepared in sealed
containers at ~24.degree. C. and when they underwent phase
separation that could be detected visually; temporal stabilities of
gels with T.sub.g below 24.degree. C. were not measured.
.sup.cTransformed to a CG at 35.degree. C..sup.19
[0234] SAFIN (self-assembled fibrillar networks) structures of HSA
organogels have been studied extensively and head-to-head contacts
between carboxylic acid groups have been shown to promote the
formation of multiple hydrogen-bonded sequences and aid fiber
stability. The Tg values of 2 wt % HSA and an n-alkane with an even
number of carbon atoms are slightly higher than those with
odd-numbered n-alkane liquids, but all were opaque in appearance.
The dependence of the SAFINs of the HSA gels on the liquid
component is apparent when silicone oil and n-alkanes are compared:
at one LMOG concentration, the silicone oil gel has a higher Tg
than the n-alkane gels. Also, the sodium salt of HSA has been found
to gelate n-dodecane at 4 wt %, and as little as 0.5 wt % was able
to gelate chloroform and carbon tetrachloride..sup.20
[0235] Intermolecular H-bonding interactions between primary or
secondary amide functional groups can be stronger than between two
carboxylic acid groups..sup.21 Thus, the Tg of n-alkane or silicone
oil gels is higher when the LMOG was one of the amides, 1-6, than
when it was HSA. Removal of the 12-hydroxyl group from 1 yields
octadecanamide (14), which, in contrast to SA, is an excellent
gelator. However, whereas 2 wt % 1 is a better gelator of
lower-polarity liquids and forms solutions with low molecular-mass
alcohols, the same concentration of 14 is a more efficient LMOG of
higher-polarity liquids and precipitates from n-alkanes.
TABLE-US-00003 TABLE 3 Appearances (AP).sup.a and Tg values
(.degree. C.) of gels formed from compounds 14-17 (wt % in
parenthesis) in various liquids. 14 (~2) 15.sup.7,8 (~2) 16.sup.7
(~3) 17.sup.8 (~2) Liquid AP Tg AP Tg AP Tg AP Tg n-Hexane P P
n-Octane P P n-Decane P Cyclohexane P TG 31 Silicone oil OG 72-74
TG 25 TG 59-60 Methanol OG 30-34.sup.b 1-Butanol OG 29-30 P TG 45 P
1-Octanol OG 29-30 P TG 39 P Betuyl alcohol OG 32-33 S TG 44
Chlorobenzene Visc Soln Chloroform Visc Soln CCl.sub.4 OG 28-30 P P
n-Perfluorooctane I Benzene OG 34-35 P TG 30-33 Toluene CG 34-36 P
TG 34 TG 47-48 DMSO OG 38-40 TG 50-52 TG 74-76 Acetonitrile OG
59.sup.b Water I .sup.aOG--opaque gel, TG--turbid gel, Visc
Soln--viscous solution, P--precipitate, I--insoluble, CG--clear
gel. .sup.bphase separation: liquid fell upon heating; some or all
solid did not.
[0236] For example, the Tg values for 2 wt % 14 gels are lower than
those of 1 in silicone oil, benzene, and toluene but are higher in
acetonitrile; in DMSO, 1 is dissolved whereas 14 forms a stable
gel. This contrasting behavior, caused by the presence or absence
of a 12-hydroxyl group along the long alkyl chain, can be traced to
the relative solubilities of the two LMOGs: 14 is more soluble in
less-polar liquids, and 1 is more soluble in more polar
liquids.
[0237] The addition of an alkyl group to the amide group of 1 has
two effects on its ability to gelate liquids: (1) the amides lose
some of their potential to create H-bonding networks because one of
the H atoms is replaced; (2) the amide group is moved from a
molecular terminus to an interior position. The general trend in
Table 1 toward lower Tg values in liquids such as silicone oil,
CCl.sub.4, chlorobenzene, benzene, and toluene as the amide
functional group of the LMOG is moved farther from a terminus
(i.e., Tg(1)>Tg(2)>Tg(3)) must be interpreted with caution;
at constant amide wt %, the molar concentrations decrease as the
length of the alkyl group increases and the number of possible
H-bonding and London dispersive interactions decreases and
increases, respectively. Possible changes in the molecular packing
arrangements within a fiber (vide infra) add other complications.
In addition, because the CGCs differ in each liquid, the total
amount, of an LMOG participating in the SAFIN of a gel will also
differ, and the variation will not be constant from gelator to
gelator.
[0238] FIG. 4 shows the Tg values versus alkyl chain length for the
gels of 1-6 in different liquids. Except for DMSO gels, the Tg
values for the primary amide (1) were higher than those of the
secondary amides with N-methyl or N-ethyl groups (2 or 3), but
further increases in the N-alkyl chain length do not appreciably
alter the Tg values. DMSO gels of 1-6 behaved differently:
Tg(6)>Tg(5)>Tg(4) and 2 wt % 1 remained soluble in DMSO at
room temperature. Again, this trend appears to be related to the
solubilities of the amides in DMSO, and there is a precedent for
such behavior in other gel systems..sup.22
[0239] H-bonding between amine groups is generally weaker than
between amides, and as mentioned above, the differences between
amino-amino and amido-amido aggregation modes may lead to changes
in the overall packing arrangements of the gelator molecules in
their fibers..sup.1 The importance of the stronger amide-amide
interactions in the stabilization of the SAFINs is evident when the
gels employing the amides (1-6) and the analogous amines (7-12) are
compared. For example, the primary amine (7) is a much less
efficient gelator than its primary amide analogue, 1; it gelates
fewer of the investigated liquids, and its gels exhibit lower Tg
values. Interestingly, 7 is also a much less efficient gelator than
the secondary amine, 8, in which a methyl group replaces one of the
H atoms on nitrogen (and thereby eliminates one potential H-bonding
interaction). FIG. 5 presents a comparison of Tg values of the gels
of 7-12 in DMSO and silicone oil. The trends in the silicone oil
gels correlate with the melting temperatures of the neat gelators.
This correlation and the very small temperature ranges for the gels
indicate that the thermodynamic driving force for supersaturated
solutions/sols in silicone oil is very large and that the gelator
molecules are able to aggregate and nucleate rapidly below Tg.
Whereas 2 wt % 7 is a viscous solution in DMSO at room temperature,
2 wt % 8 forms an opaque gel. The highest Tg value of the amine
LMOGs investigated was found for the N-butyl derivative (11), and 2
wt % 12 in DMSO formed a precipitate when cooled from its sol
phase.
[0240] 1-Octadecylamine (15), the analogue of 7 lacking a
12-hydroxy group, is known to gelate silicone oil and DMSO at 5 wt
%, and di-n-octadecyl amine (18), the corresponding analogue of
secondary amine 12, forms gels with alkanes and alcohols (among
other liquids), albeit with low Tg values. (Table 3) Thus, the
removal of the hydroxyl group (and its H-bonding interactions) from
7 or 12 reduces the gelating abilities further.
[0241] Ammonium carbamate (13), prepared by the addition of CO2 to
1-aminooctadecan-12-ol (7),.sup.6a is a less-efficient LMOG than
any of 1-12 or HSA. For example, the Tg values of silicone oil gels
with 2 wt % gelator increase in the order 13 (0-2.degree.
C.)<7<HSA. To effect self-assembly, molecules of 13 must rely
principally upon electrostatic interactions of the head groups and
H-bonding among 12-hydroxyl groups; London dispersion forces among
methylene units along the chains contribute as well..sup.1c,1g
Thus, it is somewhat surprising, given the comparisons of the
gelating abilities of 7 and 12 and their non-hydroxylated analogues
(15 and 16), that 13 is a less efficient gelator than even the
ammonium carbamate (17), which gelates silicone oil, benzyl
alcohol, toluene, and DMSO (Table 3)..sup.24 However, we note that
the Tg of the gel from 2 wt % 13 in chlorobenzene is higher than
that from even HSA, and 7 yielded no gel. Clearly, any correlation
between LMOG structure and gelator efficiency must take into
consideration some very complicated bulk and molecular aspects of
interactions with the liquid components.
Example 4
Dependence of Gel Properties on LMOG Concentration
[0242] The data in FIG. 6 show that <1 wt % of each of the LMOGs
included, except 7 and 13, is able to gelate silicone oil at room
temperature. A clear gel was formed at room temperature even at
0.06 wt % 1, and the Tg values of these gels in the "plateau"
concentration region (ca. 2-5 wt where the 3D SAFINs become more
intricate but their basic structures and interactions are not
changed appreciably') are very high, near 100.degree. C. At room
temperature, the gels remained clear to concentrations 50.5 wt %
and became increasingly opaque thereafter up to 5 wt %.
[0243] Silicone oil gels of the N-propyl amide (4) and N-octadecyl
amide (6) are opaque throughout the concentration ranges explored.
Although both are exceedingly effective gelators, their CGCs are
slightly higher (0.2 and 0.4 wt %, respectively) than that of 1.
The consequences of weaker H-bonding between amino groups of amine
gelators 7, 10, and 12 are evident in both their CGC and Tg values;
the CGC values are higher and the Tg values are lower than for the
corresponding amides.
[0244] Table 4 summarizes the CGCs, appearances, and stability
periods of silicone oil and toluene gels of 1, 4, 6, 7, 10, and 12
at room temperature.
TABLE-US-00004 TABLE 4 CGCs (wt %), Appearances (AP),.sup.a and
Periods of Stability (PS).sup.b for Silicone Oil and Toluene Gels
with LMOGs 1, 4, 6, 7, 10 and 12 Prepared Using the Fast-Cooling
Procedure. silicone oil toluene CGC AP PS CGC AP PS 1 0.1 CG 4 d
0.3 CG 2 m.sup.c 4 0.2 CG 2 m.sup.d 0.3 CG 2 m.sup.c 6 0.4 OG 16
h.sup.c 2.0 OG (syn) 5 m 7 2.0.sup.e OG.sup.e no gel 10 0.2 OG 2 w
2.0 OG 1 h 12 0.5 OG 18 h no gel .sup.aOG--opaque gel, CG--clear
gel, syn--syneresis. .sup.b Periods at ~24.degree. C. in sealed
containers between when gels were prepared and when visible phase
separation was noted; m--month, d--day, w--week. .sup.cSyneresis
after 1 h. .sup.dSyneresis after 2 weeks. .sup.eT.sub.g =
21-22.degree. C.; temporal stabilities of gels with Tg below
24.degree. C. were not measured.
[0245] These data consistently show that less LMOG is necessary to
form a gel in silicone oil than in toluene because the LMOGs are
more soluble in the latter, but there is no clear trend in the
dependence of the liquid on periods of stability. The concentration
dependence of 1 and 4 on the gelation properties in toluene has
also been examined (FIG. 7): gels using 0.2-2.0 wt % 1 were clear,
and 3-5 wt % gels were opaque in appearance; gels with 0.3-5.0 wt %
4 were transparent.
[0246] In some systems, including those in which N,N'-dialkyl ureas
are the LMOGs,.sup.15 the cooling protocol can lead to very
different SAFINs with different Tg values..sup.23,25,26 That does
not appear to be the case here. The gelation temperatures of the
HSA derivatives in silicone oil were compared when their gels (at
low and high LMOG concentrations) were prepared from their sols by
fast- and slow-cooling protocols.
TABLE-US-00005 TABLE 5 Appearances and Tg values (.degree. C., in
parenthesis) of gels of HSA derivatives in silicone oil prepared by
fast- and slow-cooling procedures. Gelator Wt % Fast-cooling Wt %
Slow-cooling 1 0.1 CG (63-64) 0.1 CG (63-65) 1 5 OG (100-101) 4.7
OG (100) 4 0.21 OG (42-45) 0.24 OG (51-54) 4 5 OG (90-92) 4.9 OG
(90-92) 6 0.42 OG (18-21) 0.42 OG (73-74) 6 5 OG (88 -90) 4.9 OG
(89-90) 10 0.21 OG (20-26) 0.19 OG (30-32) 10 5.0 OG (67-68) 5.1 OG
(67-68) 12 0.5 OG (35-37) 0.5 OG (35-38) 12 4.2 OG (72-73) 4.8 OG
(74-76) .sup.aOG = opaque gel, CG = clear gel
[0247] The Tg values were not sensitive to the cooling protocol
except for the gel with 0.42 wt % 6, where Tg=21-23 and
73-74.degree. C. for gels made by the fast- and slow-cooling
protocols, respectively. The reason for this large change appears
to be related to a change in the morphology of its SAFIN (vide
infra).
[0248] The mean temperature at which a SAFIN melts, Tm, and the
heat associated with that transition have been measured by DSC for
silicone oil gels at relatively high LMOG concentrations (in order
to observe the endothermic and exothermic peaks easily in the
thermograms). The normalized enthalpies (per gram of LMOG; see
Table 6) as well as the entropies (.DELTA.S=.DELTA.H/T.sub.m) of
the reversible transitions were calculated using the averages of
the absolute magnitudes of OH and the onset temperatures from the
first heating and cooling thermograms of the silicone oil gels and
neat solids. As expected, the Tm values of the SAFINs are always
lower than the melting temperatures of the neat LMOGs; the silicone
oil liquid aids SAFIN melting by dissolving the molecules in the
fibers over a temperature range that precedes the loss of
viscoelasticity.
TABLE-US-00006 TABLE 6 Comparison of T.sub.m, and .DELTA.H,.sup.a
and .DELTA.S of Silicone Oil Gels and Neat Solids of 1, 4, 6, 8,
and 12 during Their First Heating and Cooling, from DSC
Thermograms, and T.sub.g Values from the Falling Drop Method
heating cooling gelator conc T.sub.m (.degree. C.) .DELTA.H (kJ
mol.sup.-1) T.sub.m (.degree. C. ) -.DELTA.H (kJmol.sup.-1) T.sub.g
(.degree. C.) .DELTA.S (J mol.sup.-1 K.sup.-1) 1 4.6 wt % 100.1
51.8.sup.b 104.6 48.5.sup.b 100 134 neat 113.4 49.4 111.2 48.8 127
4 5.2 wt % 94.3 49.5.sup.c 90.0 47.5.sup.c 90-92 133 neat 107.5
55.0 101.5 53.6 144 6 5.0 wt % 91.7 86.1.sup.d 91.7 71.2.sup.d
89-90 216 neat 106.8 94.4 104.0 81.1 232 8 4.8 wt % 59.1 50.7.sup.e
60.7 43.9.sup.e 67-68 142 neat 87.6 67.4 83.8 65.5 185 12 4.8 wt %
73.1 83.4.sup.e 70.9 70.5.sup.e 74-76 223 neat 93.1 95.8 87.8 95.8
263 .sup.a.DELTA.H values from the gels are normalized to 100%
concentrations of the LMOC component by dividing the observed heats
by the quantities listed in footnotes b-e. .sup.b0.046.
.sup.c0.052. .sup.d0.05. .sup.e0.048.
[0249] Thus, the normalized heats of the gel transitions are
generally lower than those of the associated neat LMOG. Only with
the most efficient LMOG (1) do the normalized heats of the gels
approach the heats found for the neat solid. In all other cases,
the enthalpy and entropy values indicate that the dissolution of
the LMOGs as their SAFINs melt is aided somewhat by silicone oil.
In addition, the similarity between the Tm and Tg values in Table 6
indicates that the loss of the viscoelastic properties of these
gels occurs as the bulk of the LMOG molecules melt, rather than at
an earlier possible stage (e.g., when the junction zones between
the fibers of SAFIN are severed)..sup.1a,13
[0250] SAFIN Structural Information from Polarizing Optical
Microscopy and Scanning Electron Microscopy:
[0251] As has been found in many other systems, the spherulites of
gels from the HSA derivatives are larger when prepared by the
slow-cooling protocol; see, for example, the POMs in FIG. 8.
Generally, more supersaturation results in smaller and more
numerous crystals, .sup.27 and the driving force for the phase
separation of a sol, leading to nucleation, fiber growth, and SAFIN
formation, increases with increasing supersaturation (i.e., as the
reduced gelation temperature, Tg-T, for sol incubation
increases).sup.2 whereas the sizes of the basic SAFIN units (fibers
or spherulites) decrease and become more numerous or the morphology
of the LMOG objects changes..sup.25,29
[0252] The spherulitic objects of slow-cooled gels of 2 wt % 4 in
n-decane, CCl.sub.4, DMSO, or silicone oil are larger than from the
fast-cooled ones (FIGS. 9-13). The fast-cooled gels of 4 in toluene
and the 2 wt % gels of 6, 10, and 12 show spherulitic textures
similar to those of 1 in FIG. 8c (FIGS. 14-23). The much higher Tg
of the slow-cooled rather than fast-cooled gel of 0.42 wt % 6 in
silicone oil is consistent with its larger spherulites (FIG. 24).
However, the magnitude of the Tg difference for this gel, ca.
50.degree. C., is difficult to rationalize on the basis of the
sizes of the SAFIN objects alone. XRD data presented later indicate
that the molecular packing within the objects of a fast-cooled gel
with 5.0 wt % 6 in silicone oil differs from that of neat 6.
Unfortunately, the XRD method is not sufficiently sensitive to
produce useful information on slow- and fast-cooled gels at 0.42 wt
%. Also, for reasons that remain unclear, the gels of 1 in toluene
prepared by the fast-cooling protocol exhibit a spherulitic texture
(FIG. 8c) whereas the SAFIN substructure in the slow-cooled gel is
too small (<-2, um) to be seen by our optical microscope (FIG.
8d).
[0253] SEM images of xerogels prepared from representative gels
were recorded (FIG. 25). The micrographs from opaque gels of 2.0
and 0.5 wt 1 in CCl4 show fibrous structures, and that from 0.5 wt
% 1 indicates that the fibers are helical (FIG. 25b). Micrographs
from transparent gels of 2.0 and 0.5 wt % 1 in chlorobenzene also
show fibrous structures, including evidence of twisting in the more
dilute sample (FIG. 25c,d).
[0254] Molecular Packing within SAFIN Objects from X-ray
Diffraction Data:
[0255] XRD diffractograms of neat powders and fast-cooled silicone
oil gels with 5 wt % 1, 4, 6, 7, 10, 12, and 13 have been compared.
The diffraction peaks of the gels were identified by subtracting
the amorphous scattering of the silicone oil from the total gel
diffractogram..sup.30 The same morphology is present in the SAFINs
of the gels and in the neat powders if the peaks in their
diffractograms are found at the same values of 20, as is the case
for 1 (FIG. 26 a,b). However, the correspondence is less clear for
4 and 6 (FIGS. 26c-f). The lattice spacings (d, A) of the HSA
derivatives in their crystalline and silicone oil gels have been
calculated from the Bragg relationship and are summarized in Table
7. In all cases, attempts to index the diffraction peaks in Table 6
for 1, 4, 6, 7, 10, 12, and 13.sup.31 and thereby to identify the
gross natures of their cell packing were unsuccessful.
TABLE-US-00007 TABLE 7 Comparison of Lattice Spacings (d, A) of 1,
4, 6, 7, 10, 12 and 13 in the Neat Powders and Gels.sup.a (from XRD
data at 24.degree. C.) and Calculated Extended Molecular Lengths
(L, A). L.sup.32 d (powder state) d (gel state) 1 26.4 48.5, 15.7,
4.5, 3.9, 3.8 48.5, 15.7, 4.5, 3.9, 3.8 4 31.1 28.5, 14.3, 10.8,
8.2, 4.7, 4.1, 3.9, 3.6 28.5, 14.3, 4.2, 4.0, 3.8 6 50.3 23.8,
16.0, 12.2, 9.5, 8.8, 4.6, 4.1, 3.9, 3.5 46.5, 23.0, 14.0, 4.4,
3.9, 3.8, 3.7 7 27.2 47.1, 22.6, 17.2, 7.6, 7.3, 4.5, 4.2, 3.4, 3.1
17.4, 4.5, 4.1, 3.9 10 31.0 26.7, 13.6, 8.2, 6.5, 5.8, 5.0, 4.3,
4.1, 26.7, 13.6, 4.3, 4.1, 3.9, 3.6, 2.5, 2.3 3.9, 3.6, 2.5, 2.4,
2.3 12 50.2 16.0, 8.3, 7.5, 4.1, 3.7 47.7, 14.1, 4.1, 3.8 13 49.9
49.0, 16.9, 4.5, 4.1 49.0, 16.9, 4.5, 4.1 .sup.aGels prepared in
silicone oil (~5 wt %) using the fast-cooling protocol.
[0256] The Bragg distances of the low-angle peaks, indicative of
lamellar packing, represent the thicknesses of the layers. For 1,
they are slightly less than twice the calculated extended molecular
length.sup.3 (Table 6), suggesting a packing arrangement like that
in FIG. 27a. The positions of the diffraction peaks of the silicone
oil gel of 4 correspond to that of the neat powder, but the
relative intensities within the two diffractograms differ as would
be expected if the fibers of the SAFINs of 4 are oriented with
respect to the capillary walls..sup.24 (FIG. 26c and Table 7).
Consistent with a monolayer arrangement like that shown in FIG.
27b, the distances corresponding to the lowest-angle peaks in the
diffractograms are approximately the same as the calculated
extended length of one molecule of 4. Diffraction peaks of the
silicone oil gel of the corresponding N-propyl amine, 10 (FIG. 28),
correlate with those of the neat powder as well.
[0257] Additional evidence for the same morphology of the LMOGs
being present in the SAFINs and neat solid phases has been obtained
from IR studies. The NH, OH, and CO stretching band frequencies of
silicone oil gels with 5 wt % amide (1 or 4) are almost the same as
those of the neat gelator (FIG. 29). The NH stretching frequencies
of the neat powder of amine 10 and its 5 wt % gel in silicone oil
are also virtually the same. In addition, the sharpness of these IR
peaks is consistent with specific H-bonding networks in the SAFIN
fibers.
[0258] However, different diffraction peaks are found for the
silicone oil gel and neat powder of both of the N-octadecyl LMOGs,
6 (FIG. 26 e,f) and 12 (FIG. 30). For both gels, the lowest-angle
peak in the XRD pattern corresponds approximately to the calculated
extended length of one molecule and is consistent with a monolayer
packing arrangement in the SAFINs (FIG. 27c). The lowest-angle
peaks observed correspond to distances that are less than one-half
of the calculated molecular lengths. Thus, the data in hand are not
consistent with a lamellar packing arrangement that is like any of
the models in FIG. 27. However, the diffractograms of the powders
of 6 and 12 may be missing key peaks at angles lower than our
diffractometer can record.
[0259] The diffraction pattern of the aggregates of 7 in its
silicone oil gel (FIG. 31) does not coincide with that of the neat
powder. In the gel state, the low-angle peaks were very small even
after exposure of the sample to X-rays for a period much longer
than required to obtain good signal-to-noise ratios after solvent
subtraction in the other gels at the same LMOG concentration. The
layer spacing calculated from the analysis of the neat powder of 7
is slightly less than twice the calculated extended molecular
length, suggesting a bilayer packing arrangement. Finally, the
X-ray diffractograms of the neat solid and silicone oil gel of the
ammonium carbamate (13) indicate the same packing arrangement,
probably stacked layers in which one ammonium and one carbamate are
end-on (Table 6 and FIG. 32).
[0260] Rheological Properties:
[0261] The upper limit of the linear viscoelastic regime of a gel
consisting of 2 wt % 1 in silicone oil was strain amplitude
.gamma.=0.1% at angular frequency .omega.=1 rad s.sup.-1 at both 25
and 80.degree. C. (FIG. 33). Within this regime, the storage
modulus (G') is 1 order of magnitude larger than the loss modulus
(G'')--the gel is very stiff--and the G' and G'' values are
independent of the applied frequency over a range of at least
.omega.=0.01-1.0 rad s-1 from 25 to 80.degree. C. (FIG. 34). G''
and G' indicate that the gel becomes weaker with increasing
temperature, perhaps as a result of more 1 being dissolved (FIG.
6).
[0262] Strain sweep tests from .gamma.=0.01 to 100% at .omega.=1
rad s-1 were also performed for a 2 wt % 4 in silicone oil gel at
25.degree. C. The G' and G'' values remained approximately
independent of applied strain up to 0.1%. Surprisingly, as the
applied strain was increased at 45 or 75.degree. C., both G' and
G'' increased initially (FIGS. 35 and 36). These observations are
attributed to slow phase separation because the sample was visually
a mixture of solid and liquid after the experiment. A similar
frequency sweep experiment on a 2 wt % 4 in silicone oil gel showed
that G' and G'' are independent of the applied frequency at 25 and
35.degree. C. but phase separation occurs at higher temperatures
(FIG. 37).
[0263] The G' and G''' values of a 2 wt % 10 in silicone oil gel
decreased initially upon increasing strain at 25 and 50.degree. C.
(.omega.=1.0 rad s-1; FIG. 38); the 10/silicone oil gels are
mechanically less stable than the corresponding 1 and 4 gels. At
.gamma.=0.05% strain, G' and G'' of the 2 wt % 10 in silicone oil
gel were independent of the applied frequency at different
temperatures (FIG. 39), thus confirming the viscoelasticity of the
gel.
[0264] Thixotropic Properties:
[0265] Usually, organogels from LMOGs, especially those in which
the SAFINs are crystalline (as is the case here), are mechanically
weak and are easily destroyed when subjected to external mechanical
strain. Moreover, they are only weakly thixotropic, and after the
cessation of severe mechanical strain, they can be reconstructed
only by heating the mixture to its sol/solution state and cooling
to below Tg. Several recent reports have attempted to explain the
thixotropic behavior of LMOG-based organogels with crystalline
SAFINs..sup.33 In all of these cases,.sup.33a the restoration of
the gel viscoelasticity, indicating at least some reestablishment
of the SAFIN after mechanical disruption, required minutes to
hours. Surprisingly, the recovery times of the gels in this work
are much faster than previously reported in similar materials.
[0266] The linear viscoelastic moduli, G' and G'', was measured for
a 2 wt % 1 in silicone oil gel at 25.degree. C. by performing
oscillatory rheological measurements in a parallel plate geometry.
At a strain amplitude of .gamma.=0.1% and angular frequency of
.omega.=100 rad s.sup.-1, the gel is in the linear regime. Under
these conditions, we measured the gel response for 150 s and saw no
evolution of the moduli. Then, .gamma. was increased to 30% while
keeping co fixed, resulting in a loss of elasticity (FIG. 33).
These conditions were applied for 30 s. FIG. 40 shows the evolution
of G' and G'' after .gamma. is returned to the original conditions
while maintaining .gamma.=100 rad s-1. The kinetics of recovery
were too rapid to be measured by the rheometer; ca. 90% of the
original G' value (28 000-25 000 Pa) and ca. 96% of the original
G'' value (8500-8100 Pa) were recovered in less than 10 s. The
rises in G' and G'' observed from 180 to 190 s are attributed to an
instrumental artifact caused by the inertia of changing from higher
strain (30%) to lower strain (0.1%). Experiments with similar
strain profiles, .gamma.=(50, 70, 90, and 120) % and .omega.=1 rad
s.sup.-1 held for 30 s, demonstrate very similar results--the
recovery of ca. 88% of the initial G' value in less than 10 s.
Although the actual times and events responsible for this recovery
may be partially due to instrumental factors and tool slip (i.e., a
loss of contact between the sample and the metal plates of the
rheometer), the rapid recovery does not appear to be an artifact of
the measurement. To demonstrate this, a bulk sample of this gel was
severely disturbed mechanically by moving a glass rod through it
rapidly for more than 1 min. On all observable time scales, the
material remained a gel without any qualitatively discernible
change in its appearance or viscoelasticity.
[0267] Similar rheological measurements on silicone oil gels
containing 2.0 wt % HSA, 2, 4, 10, and 12 resulted in equally fast
but somewhat lower recoveries of the original G' values (Table 8
and FIGS. 41-45). The degrees of recovery correlate at least
qualitatively with the potential strength of hydrogen-bonding
interactions among the LMOGs: 1.degree. amide (1)>acid
(HSA)>2.degree. amides-(2, 4)>2.degree. amines (10, 12). In
FIGS. 41 and 42, the rises in G' and G'' observed from 180 to 190 s
are attributed to an instrumental artifact caused by the inertia of
changing from higher strain (30%) to lower strain (0.1%). In FIG.
43, the rise and decay in G' and rise in G'' observed from 600 to
610 s are attributed to an instrumental artifact caused by the
inertia of changing from higher strain (100%) to lower strain
(0.05%). In FIG. 44, The rise and decay in G' and rise in G''
observed from 180 to 190 s are attributed to an instrumental
artifact caused by the inertia of changing from higher strain
(100%) to lower strain (0.05%). In FIG. 45, the rise and decay in
G' and rise in G'' observed from 180 to 190 s are attributed to an
instrumental artifact caused by the inertia of changing from higher
strain (100%) to a lower strain (0.05%).
TABLE-US-00008 TABLE 8 Comparison of the Degree of Thixotropy of
HAS and Several of Its Derivatives at 2 wt % in Silicone Oil Gels
at 25.degree. C. % G' recovery.sup.a,b HSA 69.8 .+-. 3.2 1 90.0
.+-. 1.0 2 45.0 .+-. 9.0 4 42.5 .+-. 14.2 10 3.8 .+-. 0.3 12 9.2
.+-. 4.6 .sup.aCalculated from the ratio of the G' values after and
before applying destructive strain (30% strain amplitude and 1 rad
s.sup.-1 for HSA, 1, 12 and 100% strain amplitude, and 1 rad
s.sup.-1 for 4 and 10) for 30 s at 25.degree. C. .sup.bAverage of
three separate experiments.
[0268] As mentioned, a possible mechanism for the remarkably fast
recovery times and, in several cases, high degrees of recovery of
the viscoelastic properties includes slip or broken contacts
between the SAFINs of the gels and the metal plates of the
rheometer. To test this, we measured the recovery of G' for a gel
that is only moderately thixotropic, 2 wt % 2 in silicone oil, at
different plate separations. At all separations investigated (Table
9), the recovery was within the instrumental response time of the
rheometer, <10 s. We hypothesize that if slip or surface
destruction of the gel were responsible for the rapid recovery, G'
should decrease as the gap is increased. However, contrary to our
expectations, G' increased as the plate gap decreased. Finally, an
experiment with the same gel of 2 in silicone oil was performed
using cone-plate geometry in which the strain is constant along the
radius of the tool; there is a strain gradient along a radius in
the plate-plate geometry. The results from the cone-plate geometry
experiment are consistent with those from the 0.1 mm plate-plate
gap experiment-ca. 85% recovery of G' in less than 10 s (Table
9).
TABLE-US-00009 TABLE 9 Comparison of the Thixotropic Properties of
2 wt % 2 in Silicone Oil Gels at 25.degree. C. at Different
Parallel Plate Separations and Cone-Plate Geometry. geometry gap
(mm) % G' recovery.sup.a,b parallel plate 1.0 19.6 .+-. 1.6
parallel plate 0.5 45.0 .+-. 9.0 parallel plate 0.25 68.3 .+-. 0.9
parallel plate 0.1 83.0 .+-. 2.1 cone-plate 0.05.sup.c 86.7 .+-.
2.3 .sup.aCalculated from the ratio of the G' values after and
before applying destructive strain (30% strain amplitude and 1 rad
s.sup.-1 angular frequency) for 30 s. .sup.bAverage from two
separate experiments. .sup.cClosest contact of cone to plate.
[0269] Although the results in Table 8 point to the importance of
hydrogen-bonding interactions, the mechanism of the recovery of
these SAFINs remains unknown. In the sole literature precedent for
such behavior in organogels with crystalline SAFINs that we have
been able to find,.sup.33a N-(3-hydroxypropyl) dodecanamide in
toluene was transformed by applied strain from a jammed phase (a
gel) to an aligned phase (a sol in which the fibers are no longer
in an effective 3D network). The rate of recovery of
viscoelasticity after cessation of the destructive strain was
dependent on the prior history of the sample, but the fastest
recovery required a few minutes. The explanation given for these
results may be applicable, at least in part, to our systems as
well: the fibers of the SAFIN in the gel are joined by H-bonding
interactions along their surfaces; the applied strain can break
these interactions without destroying the fibers or a large part of
their meso structures (N. B., spherulites in our SAFINs); and
cessation of the destructive strain allows the aligned fibers (and
spherulites) to diffuse rotationally and translationally to reform
the SAFIN via renewed contacts. The fibrillar structures detected
by optical and electron microscopy for the LMOGs in our study are
compatible with such a mechanism, but they do not demand it.
[0270] The introduction of a hydroxyl group along the alkyl chain
of stearic acid (a b-type molecule in Scheme 1), as in HSA (a
c-type molecule), changes the gelating ability of an LMOG
enormously. The efficiency of the HSA-derived gelators has been
tuned further by modifying the carboxylic acid functionality of the
head group, making it 1 of 13 different nitrogen containing
moieties. The efficiencies are improved when the carboxylic acid
functionality is transformed into a primary amide (1, a c-type
molecule), but efficiency suffers when a primary amine is placed in
its stead (7, a different c-type molecule). Further changes of 1 to
a secondary amide (2 or 3; molecules intermediate between c- and
d-types) lead to decreased overall efficiencies, and increasing the
alkyl chain length of the N-alkyl group of the secondary amide
(i.e., from methyl in 2 to N-octadecyl in 6, a d-type molecule)
decreased the range of the liquids gelated further. Removal of the
hydroxyl group in 1 yields stearamide (14, a b-type molecule), a
very good LMOG that gelates a somewhat different set of liquids
than 1 or HSA. The major differences in the gelated liquids can be
understood on the basis of solubility considerations.
[0271] The importance of the ability of the head groups to act as
both H-bonding donors and acceptors is demonstrated by the higher
efficiency of the amides (1-6) than that of their corresponding
amines (7-12) and ammonium carbamate 13. Furthermore, the link
between the ability to establish a strong H-bonding network along
the octadecyl chains.sup.12a and a robust SAFIN is indicated by
comparisons of the gelator efficiencies of the HSA and
corresponding SA derivatives. The IR spectral data are consistent
with this interpretation because the NH, OH, and CO stretching
bands are sharp (FIG. 29), indicative of specific modes of
H-bonding. However, our observation that the ammonium carbamate
with pendant hydroxy groups (13) is an inferior gelator to the one
without hydroxy groups (17) suggests that the pendant group
interactions are not always beneficial to gelation. Two possible
reasons in the present case are (1) the secondary H-bonding network
from the hydroxyl groups is established and imposes restraints on
molecular packing that are not conducive to fiber (and SAFIN)
formation and (2) the hydroxyl groups interact with the charged
centers and lead to nonfibrous packing motifs..sup.18
[0272] The primary headgroup interactions in the ammonium carbamate
13 are electrostatic in nature and, for that reason, potentially
stronger than H-bonding in several of the low polarity liquids
gelated. However, 13 is a much less efficient gelator than the
amides or amines. We suspect that the density of charges in the
proximity of the head-group regions within the SAFIN fibers
attenuates cationic-anionic charge stabilization. In other systems
where the organization of charged head groups and their counterions
within planes are known and the planes are separated by layers of
long alkyl chains (as they appear to be here), the degree of
stabilization is dependent on how well the opposite charges are
able to adopt an alternating pattern..sup.34 Although we lack the
structural information within the fibers of 13 to make a
substantive model, we conjecture that such a pattern is not
achieved in the fibers of 13, perhaps as a consequence of packing
constraints imposed by H-bonding networks of hydroxyl groups along
the octadecyl chains.
[0273] As indicated by optical microscopy, differential scanning
calorimetry, and X-ray diffractometry, the packing within the gel
fibers of 1-13 is crystalline. Comparisons between X-ray
diffractograms of the SAFINs of silicone oil gels and the neat
powders of the LMOGs demonstrate that the same morphology is
obtained in all cases except for 6 and 12. Unfortunately, our
efforts to grow diffraction-quality single crystals have not been
successful thus far, and the exact nature of the packing within
fibers is not known..sup.28 However, the low-angle diffraction
peaks indicate that almost all of the LMOGs studied here pack in
layers within their gel fibers.
[0274] Another interesting observation is that some of these
organogels recover their viscoelasticity very rapidly after being
destroyed by shear. For example, gels of 2 wt % 1 in silicone oil
recovered ca. 90% of their original viscoelasticity within 10 s
after the cessation of destructive shear, and several other gels
recovered less viscoelasticity but equally fast. The fastest
reversibility of which we are aware in other thixotropic organogels
with crystalline SAFINs requires at least minutes.
[0275] Taken in total, our results suggest that the stabilization
afforded by H-bonding in amide networks is the most important
factor in determining stabilities within their SAFINs. By limiting
the H-bonding networks within a fiber to one donor per molecule,
the N-alkyl groups of the secondary amides and amines also affect
the shapes of the SAFIN fibers. In addition, the comparisons of
gelator efficiency and stability when no, one, and two potentially
strong anchoring points are placed along an alkane chain
demonstrate that more is not always better! The stabilization
gained when two or even several molecules aggregate can be lost
when they are forced to pack efficiently in a crystalline matrix.
The design of efficient gelators must take into consideration
extended matrix effects, as has been done in a few examples thus
far..sup.1b,1d
[0276] As a result of these attributes and the fact that organogels
were formed at exceedingly low LMOG concentrations in a variety of
liquids, these amides (and perhaps amines) maybe useful as
substitutes for HSA in its industrial applications,.sup.35 or they
may open the possibility of new applications. Perhaps most
importantly is that the comparisons made among HSA and its
derivatives 1-13 with SA and its derivatives 14-16, both pairwise
and in series, provide a comprehensive picture of the factors
leading to the stability of these organogels. However, several
unanticipated and challenging questions have arisen from the work
presented here: there are general trends that can be extracted from
correlations between the structure types in Scheme 1 and the
properties of the gels formed, but a priori predictions of which
LMOG will gel which liquid and what the properties of the gel will
be remain elusive goals. That is the case even within the
well-controlled series of simple LMOG structures examined here.
[0277] Efficient ambidextrous gelators of water and organic
solvents based on n-alkyl-n-(R)-12-hydroxyoctadecyl-ammonium salts
were prepared from (R)-12-hydroxystearic acid, a renewable
feedstock obtained from castor oil. The structures of the compounds
(18-32) are shown in FIG. 48.
[0278] Organo/hydro gels are thermo reversible viscoelastic
materials consisting of low molecular weight gelators self
assembled into complex three-dimensional structures. Different
forms of molecular gels are common in everyday life for their
applications ranging from personal care products (toothpaste,
shampoo), foodstuffs (jellies, puddings), electronic devices, and
drug delivery vehicles (gel capsules for vitamin E). Only few
gelators have capability to exhibit gelation property in water and
organic solvents. Less than 1 wt % of the salts described above are
able to gel water and a wide variety of organic liquids with equal
efficiency. (FIG. 50).
Gelation properties of the salts 18-25 in different liquids are
given in Table 10. Many of the gelators form hydrogels as well as
organogels, i.e., they are `ambidextrous`. Tge/values of the 2 wt %
hydrogels increase in the order of increasing their N-alkyl chain
length (that is 20<21<22<23, FIG. 49). This trend appears
to be related to the solubility of gelator molecules in water.
Further increasing of N-alkyl chain from N-pentyl to N-hexyl
increase in the hydrophobic interactions that consequence in the
formation of precipitate. For the similar reason the compound
having N-octadecyl chain (8) did not gelate water. All the gelators
(19 to 24) except 18 gelate CCl.sub.4 and toluene forming
translucent and transparent gels respectively. A 2 wt % of 18 form
a viscous solution in CCl.sub.4 and clear solution was observed in
toluene. In CCl.sub.4 and toluene Tgel value does not significantly
vary for the gelators 19-22. Slightly low Tgel value was observed
for the gelators 6 and 8 in CCl.sub.4 and toluene compare to the
gelators 19-22 under similar condition, which may be because of
difference in solubility of the gelators (FIG. 49).
[0279] FIG. 3 (I) show concentration versus gel melting
temperatures of 4 in toluene and water gels. Concentration
dependent studies of 8 in toluene gels were also studied (FIG. 50
(II).
TABLE-US-00010 TABLE 10 Appearances,.sup.a Tgel values (.degree.
C.).sup.b, and periods of stability.sup.c (in parentheses) of
fast-cooled gels containing ~2 wt % of gelator in various liquids.
Solvent 18 19 20 21 22 23 24 25 Water Visc Soln Visc Soln OG (57,
>8 m) OG OG OG P P (76-77, >8 m) (83, >3 m) (94, >2 m)
Methanol Soln Soln Soln Soln Soln Soln Soln OG (32-34, >8 m)
1-Butanol Soln Soln Soln Soln Soln Soln Soln TG (34-35, 1 m)
1-Octanol Visc Soln P P P P TG TG (28-29) TG (29-32, >2 m)
(40-43, >8 m) Benzyl alcohol Soln Soln Soln Soln Soln Soln Soln
CG (33-35, 1 m) Acetonitrile P P OG OG OG OG OG (71-72) P (73-74,
>6 m) (76.sup.d, >6 m) (67, >3 m) (78-79, >2 m)
CCl.sub.4 Visc Soln TG TG TG TG TG TG (69) TG.sup.e (76, >6
m.sup.f) (76-77, >6 m.sup.f) (76-77, >6 m.sup.f) (73, >3
m) (72, >2 m) (55, >6 m) Toluene Soln CG (syn. CG CG CG CG CG
(68-69) CG 74-75 >8 m) (77-78, >8 m) (77-78, >8 m) (74,
>3 m) (72-73, >2 m) (60, >8 m) n-Hexane I I I I I I I CG
(83, >2 w) n-Dodecane P P P I I I P Visc Soln Cyclohexane I P P
P P P P OG (70-71, >2 w) .sup.aOG--opaque gel, Syn--syneresis,
Soln--solution, Visc--viscous, P--precipitate, TG--translucent gel,
CG--clear gel, m--month. .sup.bTgel--gel melting temperature
obtained from falling drop method and the temperature ranges
indicate when the initial and final portions of an inverted gel
sample fell on being heated slowly. .sup.cThe periods of stability
are being measured as the time between when gels were prepared in
sealed containers at ~24.degree. C. and when they underwent phase
separation that could be detected visually. .sup.dphase separation
was observed. .sup.eGel was formed after keeping the sol for ~1 w
at 22.degree. C. .sup.fsyneresis after 5 months
[0280] To study the effect of different counter ions on the
gelation properties, ammonium salts 9-15 were prepared. Table 10
show gelation properties of 9-15 in various liquids.
TABLE-US-00011 TABLE 11 Appearances,.sup.a Tgel values (.degree.
C.).sup.b, and periods of stability.sup.c (in parentheses) of fast-
cooled gels containing ~2 wt % of gelator in various liquids. 26,
27, 28, 29, 30, 31, 32, Solvent X = Br X = I X = NO.sub.3 X =
BF.sub.4 X = Acetate X = Octanoate X = Oxalate Water OG P OG OG
Visc Soln P OG (83-84, >1 m) (80-81, >1 m) (81, >1
m).sup.d (98-99.sup.e, >1 m) Methanol Soln Soln Soln Soln Soln
Soln P 1-Butanol P Soln Soln P Soln Soln P 1-Octanol P P Soln P P
Soln Visc Soln Benzyl Soln Soln Soln Soln Soln Soln Soln alcohol
Acetonitrile OG P P Soln P P I (61-62, >1 m) CCl.sub.4 TG Soln
TG Soln CG CG Soln (74, >1 m) (59, >1 m) (76.sup.c, >1 m)
(74-76.sup.c, >1 m) Toluene CG Soln Soln Soln Soln Soln P (69,
>1 m) Cyclohexane P I P P P P I n-Dodecane I I P I P P I
n-Hexane I I I I P P I .sup.aOG--opaque gel, Soln--solution,
Visc--viscous, P--precipitate, TG--translucent gel, CG--clear gel,
I--insoluble, m--month. .sup.bTgel--gel melting temperature
obtained from falling drop method and the temperature ranges
indicate when the initial and final portions of an inverted gel
sample fell on being heated slowly. .sup.cThe periods of stability
are being measured as the time between when gels were prepared in
sealed containers at ~24.degree. C. and when they underwent phase
separation that could be detected visually. .sup.d5 wt %.
.sup.ephase separation was observed.
[0281] POM images of a 5 wt % fast- and slow-cooled transparent gel
of 21 in toluene gel show a spherulitic texture (FIGS. 51A and 4B).
This reveals that the network structure present in the gel is
crystalline in nature. More super saturation increased the effect
in nucleation of crystal growth and produce larger fibers. The size
of the objects is apparent comparing the POM image of a gel
prepared by a slow-cooled protocol (FIG. 51B) with the gel prepared
by fast-cooled protocol (FIG. 51A). Larger spherulitic image is
observed in the latter case. An opaque hydrogel obtained from 5 wt
% 21 also exhibit spherulites and smaller and larger and
spherulitic images were observed for the samples prepared using a
fast- and slow-cooled protocol (FIG. 51C and FIG. 51D). FIG. 51E
show POM image of a translucent gel of 1.9 wt % of 25 in octanol. A
spherulitic image was seen for the slow cooled sample of 1.9 wt %
of 25 in octanol.
[0282] XRD diffractograms of neat powders and fast-cooled hydrogels
with .about.5 wt % 21 have been compared. The diffraction peaks of
the networks of the gels were identified by subtracting the
scattering pattern of the water from the total gel diffractogram.
XRD reflection pattern of the hydrogel of 21 is identical with that
of the neat 21 (FIG. 52A, b and FIG. 52A, c) which show that same
packing is present in the hydrogel networks and in neat solid
gelator. The lattice spacings (d, .ANG.) of the hydrogel of 21 and
21 in powder state have been calculated from the Bragg relationship
and are summarized in Table 12.
TABLE-US-00012 TABLE 12 Lattice spacings (d, .ANG.) of 20, 21 and
25 in their neat powders and ~5 wt % gels.sup.a (from XRD data at
22.degree. C.) and calculated extended molecular lengths (L,
.ANG.).sup.5. Compound solvent L d 20 neat solid 29.3 31.5, 13.1,
9.0, 6.9, 5.0, 4.3, 4.0, 3.5 20 water 29.3 31.5, 13.1, 6.9, 5.0,
4.3, 4.0 21 neat solid 30.5 31.6, 13.5, 9.4, 7.2, 4.9, 4.0, 3.5 21
water 30.5 31.6, 13.5, 9.4, 7.2, 4.9, 4.0, 3.5 21 toluene 30.5
55.2, 27.5, 13.8, 5.1, 4.5, 3.5 25 neat solid 49.9 42.8, 21.4,
14.2, 4.9, 4.4, 3.9, 3.5 25 octanol 49.9 49.3, 4.5, 3.9 .sup.aGels
prepared using the fast-cooling protocol.
[0283] The distances corresponding to the lowest angle peaks in the
diffractograms are approximately the same as the calculated
extended length of one molecule for the hydrogel of 21 and neat
gelator (Table 12), suggesting a monolayer packing arrangement like
that in FIG. 6a. It should be noted here that FIG. 53a is a primary
aggregate structure and to stabilize the network structure of 21 in
hydrogel hydrophilic ammonium moiety of 21 should face to the
solvent, and form inter-digitated bilayer structure. This kind of
bilayer arrangement structures were reported for amphiphilic
molecules in water. X-ray diffraction diagram of a 5.0 wt % gel of
21 in toluene is remarkably different from that obtained in water,
with a sharp peak appearing at 55.2 .ANG. in the small-angle region
(FIG. 52A, a). Other obtained long spacings (c/) of the 21 in
toluene gels are 27.5 .ANG. and 13.8 .ANG., corresponding to the
ratio of 1:1/2:1/4. 55.2 .ANG. is smaller than twice that of the
extended molecular length of 21, but larger than the length of one
molecule. The toluene gel thus, should maintain an inverse bilayer
structure with a thickness of 55.2 .ANG.. This value is compatible
with an inverse bilayer structure as shown in FIG. 53B. The
compound 8 did not form hydrogel because of the increase in
hydrophobic character due to octadecyl chain. The fast cooled
opaque gel of 25 in octanol exhibit a small angled peak at 49.3
.ANG. (FIG. 53B, c). This d-spacing value matches with the
calculated molecular length (49.9 .ANG.) suggesting a packing
arrangement like that in FIG. 6c. Other sharp reflection peaks
observed at wide angle region (4.5 .ANG. and 3.9 .ANG., FIG. 52B,
c) for the 25-octanol gel support the view that long alkyl chain
groups' form highly ordered layer packing as shown in FIG. 6C. The
position of the long spacings (d) of the neat powder of 25 are at
42.8 .ANG., 21.4 .ANG. and 14.2 (FIG. 53B, a), corresponding to the
ratio of ratio of 1:1/2:1/3.
[0284] The upper limit of the linear viscoelastic regime of a gel
consisting of 2.1 wt % 21 in hydrogel was ca. 0.5% strain at 1
rad/s (at 25.degree. C.) and under similar conditions yield strain
obtained for the toluene gel was 0.2% (FIG. 54A). This shows that
hydrogel of 21 is mechanically stronger compare to its toluene gel.
At higher strain % these gels were phase separated. Storage modulus
(G') and loss modulus (G'') values are independent of the applied
frequency over a range of at least 0.01-100 rad/s at 25.degree. C.
at 0.1% strain (FIG. 54B) confirming its viscoelastic behavior.
Table 13 summarizes comparison of the rheological properties of the
hydrogel and toluene gel of 21.
TABLE-US-00013 TABLE 13 Comparison of rhelogical properties
(storage modulus, loss modulus, yield strain and tan.delta.) of 2.1
wt % of hydrogel and toluene gel of 21 at 1 rad/s frequency. Yield
Solvent G', Pa G'', Pa strain, % tan .delta. Water 3.2 .times. 10
.sup.5 7.0 .times. 10 .sup.4 0.5 0.03 Toluene 9.3 .times. 10 .sup.4
1.6 .times. 10 .sup.4 0.2 0.17
[0285] The effect of each of the four compounds below on an
oil-water mixture was evaluated.
##STR00042##
About 5 drops of motor oil (Drydene Motor Oil) was added to
approximately 2 ml of tap water in a glass vial. For each of the
compounds shown above, about 1-2 mg of the compound was dissolved
in few drops of methanol, then added to the oil-water mixture
described above. The vial was maintained at 23.degree. C. and the
following observations were noted.
TABLE-US-00014 TABLE 14 Results of the investigation Compound
Result 1 Gelled oil but precipitated in water 2 Partial gel formed
and precipitated in water 3 Gelled oil completely and formed easily
removable thick aggregates 4 Gelled oil completely and formed
easily removable thick aggregates.
[0286] While exemplary articles and methods have been described in
detail with reference to specific embodiments thereof, it will be
apparent to those skilled in the art that various changes and
modifications can be made, and equivalents employed without
departing from the scope of the pending claims.
[0287] Each publication, text and literature article/report cited
or indicated herein is hereby expressly incorporated by reference
in its entirety. In addition, the books "The Basics of Oil Spill
Cleanup", Second Edition, Mery Fingas Ed., CRC Press 2 edition
(Sep. 28, 2000), "2010 Ultimate Guide to Oil Spill Cleanup
Techniques and Procedures" (Ringbound Book and DVD-ROM), U.S.
Government Author, Progressive Management; "Encyclopedia of Oil
Spill Cleanup, Response, and Environmental Restoration--Official
Guides and Manuals on Containment, Countermeasures, and Cleanup for
Coastlines, Marshes, Wildlife" U.S. Government Author, 2010,
Progressive Management; "Handbook for oil spill protection and
cleanup priorities", Jon D. Byroade (Author), University of
Michigan Library (Jan. 1, 1981); and "Oil spill cleanup and
protection techniques for shorelines and marshlands (Pollution
technology review)", Noyes Data Corp (1981) including the
supporting documentation, are hereby expressly incorporated by
reference in its entirety.
[0288] While the invention has been described in terms of various
specific and preferred embodiments, the skilled artisan will
appreciate that various modifications, substitutions, omissions,
and changes may be made without departing from the spirit thereof.
Accordingly, it is intended that the scope of the present invention
be limited solely by the scope of the following claims, including
equivalents thereof.
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